[llvm] [docs] Add documentation for LLVM Qualification Group (PR #145331)

[Kristof Beyls via llvm-commits]

https://github.com/kbeyls approved this pull request.

This looks good to me, thanks!
Can you merge this PR yourself? If not, I'm happy to do it for you.

https://github.com/llvm/llvm-project/pull/145331