[mlir] switch transform dialect ops to use TransformTypeInterface

Use the recently introduced TransformTypeInterface instead of hardcoding
the PDLOperationType. This will allow the operations to use more
specific transform types to express pre/post-conditions in the future.
It requires the syntax and Python op construction API to be updated.
Dialect extensions will be switched separately.

Reviewed By: nicolasvasilache

Differential Revision: https://reviews.llvm.org/D135584