1788: ci: Add commit format checker r=CohenArthur a=CohenArthur
Bring over the commit checker from `gcc-patch-dev` with the `gccrs` prefix checker enabled only for `gcc-patch-dev` PRs. I'll open up an issue to make sure that in the future it's easier to keep that folder in sync between the two branches
Co-authored-by: Arthur Cohen <arthur.cohen@embecosm.com>