Adding DWARF to Solana Move compiler

[jcivlin]

This is to set foot in Dwarf generating for Solana Move compiler. DIBuilder is created and will be used to accumulate more Dwarf information.

With this patch we have something as simple as:

sol@dev-equinix-new-york-2:~/tmp/090623:$ less ~/tmp/090623/0x1__unit_test.ll.debug_info

; ModuleID = '0x1__unit_test.dbg_info'
source_filename = "/home/sol/work/git/move-090523/language/move-stdlib/sources/unit_test.move"

!llvm.dbg.cu = !{!0}

!0 = distinct !DICompileUnit(language: DW_LANG_Rust, file: !1, producer: "move-mv-llvm-compiler", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, sysroot: "/")
!1 = !DIFile(filename: "unit_test.move", directory: "/home/sol/work/git/move-090523/language/move-stdlib/sources")

[ksolana]

talked to Jan, he will add test case as a separate pr.

[jcivlin]

Thx for a quick review!