[llvm-branch-commits] [compiler-rt] Convert Maintainers.txt into Maintainers.md (PR #119169)

[Vitaly Buka via llvm-branch-commits]

https://github.com/vitalybuka created https://github.com/llvm/llvm-project/pull/119169

Structured similarly to llvm/Maintainers.md.

PR has no intent to change any component maintenter.