Making the library language/compiler agnostic

[LPeter1997]

Description

As I have raised in #278 , it would be nice to make the library extensible and language-agnostic, since it's pretty easy to develop .NET languages. Long story short, as I've started fleshing out the idea, basically implemented my proposed solution. Users can register ICompilerOptionsParsers through AnalyzerManagerOptions to extend with a compiler. The 3 compilers already supported (Roslyns C# and VB, FSC) are in the list by default.

[Corniel]

I disagree with dropping this. I would propose to keep CompilerLanguage but convert it to a (Single Value Object) readonly struct. That was not needed yet, but with your proposed solution, it will be.

[Corniel]

I really like the idea of opening up Buildalizer for different languages. I'm not sure yet about the proposed solution. There are a lot of changes in here, all requiring attention. It ols means a lot of breaking changes. We should investigate how we reduce the pain for users when they have to migrate.

[phmonte]

@LPeter1997 It's a big change, as I mentioned in the issue, I like the idea, but we need to evaluate this PR very carefully to ensure the next steps.
This is on my list, I just ask for patience, I promise to evaluate it as quickly as possible.

[Corniel]

I tried an alternative approach, that involves less drastic changes. See #285