[llvm] [Offload] Introduce offload-tblgen and initial new API implementation (PR #108413)

[Jan Patrick Lehr via llvm-commits]

jplehr wrote:

> Agreed, I think this is a good way to balance things. I'll make sure to add a test/check target to this PR so we can immediately have it covered by CI.

I am working on enabling the whole `offload` project in precommit CI. However, I'm not there yet and have hit a few roadblocks along the way. Those are mostly due to the way how we use CMake and pick-up all sorts of OpenMP CMake variables.
So, I'm looking at this, but unsure about the timeline for now.

https://github.com/llvm/llvm-project/pull/108413