[clang] [clang-tools-extra] [clang-tidy] Add SARIF output to clang-tidy (PR #219182)

[via cfe-commits]

matthew-j-code wrote:

> Thanks for working on this! I left a few initial comments below.
> 
> I'm also comparing the SARIF output against the regular text diagnostics on several real-world codebases. I'll share the results and reproducer details via GitHub Gists once the runs and analysis are complete.

I've ran CTIT on this, now also working on fixing a few issues that its uncovered.

https://github.com/llvm/llvm-project/pull/219182