build: enforce minimum versions of libgmp based on arch and platform

[kwvg]

Motivation

bls-signatures#52 was merged in due to a bug in libgmp (source) that resulted in erratic behavior certain macOS environments. This has since been resolved with GMP 6.3.0 (source) and is available with Homebrew (source). Ubuntu 20.04 (focal) distributes GMP 6.2.0 (source) and Debian 11 (bullseye) distributes GMP 6.2.1 (source) and these versions work fine with dashbls in their respective environments.

As the bug only affects Apple Silicon Macs running macOS Ventura and above, we need to test against a minimum version differentiated by platform and architecture. This pull request aims to do that.

Additional Information

• Depends on https://github.com/dashpay/bls-signatures/pull/91
• The minimum version of GMP for Apple Silicon (aarch64) macOS hosts will be 6.3.0 regardless of macOS version and 6.2.0 on all other platforms.

[UdjinM6]

Needs 738d187359b33de175c552017d081c0d3d7902ef from #91 (to build it with gmp installed) and also b4cefa6c684f5e331a64f44e22b57e0f9d342fd0 (to build it w/out gmp installed and auto/no backend specified).

[UdjinM6]

2 more suggestions, pls check fb6c2d5 and 7f1a715