[llvm] [mlir] [mlir] split transform interfaces into a separate library (PR #85221)

[Stella Laurenzo via llvm-commits]

stellaraccident wrote:

> Right, to me this was only a question of maturity. Something like the transform dialect is just are core infra as the patterns mechanism, PDL, etc.

I know there are strong counter opinions to this, even with respect to PDL. I believe we've rushed maturity on some of these more speculative pieces and they would have been better to have had more mileage before integration.

https://github.com/llvm/llvm-project/pull/85221