[clang] [analyzer][NFC] Introduce framework for checker families (PR #139256)

[Balazs Benics via cfe-commits]

steakhal wrote:

> I handled all the inline comments.
> 
> I have one minor architectural question: we should standardize a way to assign a single tag description (that is, an identifier that can be used in debug dumps) to each checker family. The old code automatically used the name of the first checker part as the tag description (which was not very elegant...); while in the current version of this patch subclasses of `CheckerFamily<>` override `getTagDescription()` and return their class name as a hardcoded string literal. I think this approach is acceptable, and if we keep it then I'll add a comment in `CheckerFamily` which says that subclasses must override `getTagDescription()` this way. However, I also feel that there might be a better solution -- @steakhal what do you think?

I'll think about this, but overall I'd prefer simplicity for defining Checkers - which may make magic behind the doors slightly more involved.

https://github.com/llvm/llvm-project/pull/139256