SCons: Detect msvc compiler version

[Repiteo]

Expands the functionality of get_compiler_version by supporting msvc as an environment. Currently sets the display version to major/minor/patch as it's a 3-int tuple already, and the full version is assigned to metadata1. Doing so allows us to cutoff unsupported Visual Studio versions (anything earlier than modern VS2017) like we do with GCC/Clang. What's more, we can apply a C standard for msvc on supported versions (16.8 and later).

During this process, I also created the CompilerVersion class, which replaces the previous dictionary implementation. This grants proper type-awareness & helped cleanup redundancies in both get_compiler_version and any script using that function.

[akien-mga]

Nice work, I've also been meaning to refactor the compiler version checks a bit.

One thing worth looking into, is what info SCons already collected with their own hacky methods:

We may be able to replace some of our hacky calls to CXX to try to get version information by just using what SCons knows, provided that it's more or at least as reliable as what we currently have.

[Repiteo]

I'll do some checks with those environment variables to see if they line up with what we end up pulling. If they do, that simplifies matters significantly.

[Repiteo]

Converted to draft because it seems like SCons' hacky methods check msvc specifically, rather than trying to pull the Visual Studio version. I haven't considered how these configuations would appear to someone who only uses buildtools instead of the full Visual Studio setup & I'm not certain how that could best be tested atm.