[mlir][TilingInterface] Add pattern to tile using TilingInterface and...

[mlir][TilingInterface] Add pattern to tile using TilingInterface and implement TilingInterface for Linalg ops.

This patch adds support for tiling operations that implement the
TilingInterface.
- It separates the loop constructs that are used to iterate over tile
  from the implementation of the tiling itself. For example, the use
  of destructive updates is more related to use of scf.for for
  iterating over tiles that are tensors.
- To test the transformation, TilingInterface is implemented for
  LinalgOps. The separation of the looping constructs used from the
  implementation of tile code generation greatly simplifies the
  latter.
- The implementation of TilingInterface for LinalgOp is kept as an
  external model for now till this approach can be fully flushed out
  to replace the existing tiling + fusion approaches in Linalg.

Differential Revision: https://reviews.llvm.org/D127133