Allow to load dub.selections.json before Project instantiation

[Geod24]

The aim of this commit is to have at least one constructor for Project that does not perform IO. By moving the IO to the Dub class, we can keep the dependency injection in Dub and PackageManager only, and don't have to specialize Project.

[github-actions[bot]]

✅ PR OK, no changes in deprecations or warnings

Total deprecations: 14

Total warnings: 0

Build statistics:

 statistics (-before, +after)
 executable size=5314384 bin/dub
-rough build time=66s
+rough build time=64s

Full build output

``` DUB version 1.34.0, built on Oct 15 2023 LDC - the LLVM D compiler (1.35.0): based on DMD v2.105.2 and LLVM 16.0.6 built with LDC - the LLVM D compiler (1.35.0) Default target: x86_64-unknown-linux-gnu Host CPU: znver3 http://dlang.org - http://wiki.dlang.org/LDC Registered Targets: aarch64 - AArch64 (little endian) aarch64_32 - AArch64 (little endian ILP32) aarch64_be - AArch64 (big endian) amdgcn - AMD GCN GPUs arm - ARM arm64 - ARM64 (little endian) arm64_32 - ARM64 (little endian ILP32) armeb - ARM (big endian) avr - Atmel AVR Microcontroller bpf - BPF (host endian) bpfeb - BPF (big endian) bpfel - BPF (little endian) hexagon - Hexagon lanai - Lanai loongarch32 - 32-bit LoongArch loongarch64 - 64-bit LoongArch mips - MIPS (32-bit big endian) mips64 - MIPS (64-bit big endian) mips64el - MIPS (64-bit little endian) mipsel - MIPS (32-bit little endian) msp430 - MSP430 [experimental] nvptx - NVIDIA PTX 32-bit nvptx64 - NVIDIA PTX 64-bit ppc32 - PowerPC 32 ppc32le - PowerPC 32 LE ppc64 - PowerPC 64 ppc64le - PowerPC 64 LE r600 - AMD GPUs HD2XXX-HD6XXX riscv32 - 32-bit RISC-V riscv64 - 64-bit RISC-V sparc - Sparc sparcel - Sparc LE sparcv9 - Sparc V9 spirv32 - SPIR-V 32-bit spirv64 - SPIR-V 64-bit systemz - SystemZ thumb - Thumb thumbeb - Thumb (big endian) ve - VE wasm32 - WebAssembly 32-bit wasm64 - WebAssembly 64-bit x86 - 32-bit X86: Pentium-Pro and above x86-64 - 64-bit X86: EM64T and AMD64 xcore - XCore Upgrading project in /home/runner/work/dub/dub/ Starting Performing "release" build using /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/ldc2 for x86_64. Building dub 1.35.0-rc.1+commit.30.g1e956cce: building configuration [application] source/dub/dependency.d(908,18): Deprecation: scope variable `this` assigned to non-scope parameter `oth` calling `opEquals` source/dub/dependency.d(911,30): Deprecation: scope variable `this` assigned to non-scope parameter `a` calling `doCmp` source/dub/dependency.d(912,27): Deprecation: scope variable `this` assigned to non-scope parameter `b` calling `doCmp` source/dub/dependency.d(930,26): Deprecation: scope variable `this` assigned to non-scope parameter `oth` calling `opEquals` source/dub/internal/configy/Exceptions.d(130,34): Deprecation: reference to local variable `buffer` assigned to non-scope anonymous parameter source/dub/internal/configy/Exceptions.d(134,34): Deprecation: reference to local variable `buffer` assigned to non-scope anonymous parameter source/dub/internal/configy/Exceptions.d(248,27): Deprecation: `@safe` function `formatMessage` calling `formattedWrite` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/write.d(537,34): which calls `std.format.spec.FormatSpec!char.FormatSpec.writeUpToNextSpec!(void delegate(in char[]) @safe).writeUpToNextSpec` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): which wouldn't be `@safe` because of: /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): scope variable `this` assigned to non-scope parameter `e` calling `put` source/dub/internal/configy/Exceptions.d(250,27): Deprecation: `@safe` function `formatMessage` calling `formattedWrite` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/write.d(537,34): which calls `std.format.spec.FormatSpec!char.FormatSpec.writeUpToNextSpec!(void delegate(in char[]) @safe).writeUpToNextSpec` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): which wouldn't be `@safe` because of: /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): scope variable `this` assigned to non-scope parameter `e` calling `put` source/dub/internal/configy/Exceptions.d(283,27): Deprecation: `@safe` function `formatMessage` calling `formattedWrite` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/write.d(537,34): which calls `std.format.spec.FormatSpec!char.FormatSpec.writeUpToNextSpec!(void delegate(in char[]) @safe).writeUpToNextSpec` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): which wouldn't be `@safe` because of: /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): scope variable `this` assigned to non-scope parameter `e` calling `put` source/dub/internal/configy/Exceptions.d(286,27): Deprecation: `@safe` function `formatMessage` calling `formattedWrite` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/write.d(537,34): which calls `std.format.spec.FormatSpec!char.FormatSpec.writeUpToNextSpec!(void delegate(in char[]) @safe).writeUpToNextSpec` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): which wouldn't be `@safe` because of: /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): scope variable `this` assigned to non-scope parameter `e` calling `put` source/dub/internal/configy/Exceptions.d(323,31): Deprecation: `@safe` function `formatMessage` calling `formattedWrite` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/write.d(537,34): which calls `std.format.spec.FormatSpec!char.FormatSpec.writeUpToNextSpec!(void delegate(in char[]) @safe).writeUpToNextSpec` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): which wouldn't be `@safe` because of: /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): scope variable `this` assigned to non-scope parameter `e` calling `put` source/dub/internal/configy/Exceptions.d(325,31): Deprecation: `@safe` function `formatMessage` calling `formattedWrite` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/write.d(537,34): which calls `std.format.spec.FormatSpec!char.FormatSpec.writeUpToNextSpec!(void delegate(in char[]) @safe).writeUpToNextSpec` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): which wouldn't be `@safe` because of: /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): scope variable `this` assigned to non-scope parameter `e` calling `put` source/dub/internal/configy/Exceptions.d(332,31): Deprecation: `@safe` function `formatMessage` calling `formattedWrite` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/write.d(537,34): which calls `std.format.spec.FormatSpec!char.FormatSpec.writeUpToNextSpec!(void delegate(in char[]) @safe).writeUpToNextSpec` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): which wouldn't be `@safe` because of: /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): scope variable `this` assigned to non-scope parameter `e` calling `put` source/dub/internal/configy/Exceptions.d(335,31): Deprecation: `@safe` function `formatMessage` calling `formattedWrite` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/write.d(537,34): which calls `std.format.spec.FormatSpec!char.FormatSpec.writeUpToNextSpec!(void delegate(in char[]) @safe).writeUpToNextSpec` /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): which wouldn't be `@safe` because of: /opt/hostedtoolcache/dc/ldc2-1.35.0/x64/ldc2-1.35.0-linux-x86_64/bin/../import/std/format/spec.d(258,33): scope variable `this` assigned to non-scope parameter `e` calling `put` Linking dub STAT:statistics (-before, +after) STAT:executable size=5314384 bin/dub STAT:rough build time=64s ```