[mlir][Linalg] Add a TileToForeachThread transform.

This revision adds a new transformation to tile a TilingInterface `op` to a tiled `scf.foreach_thread`, applying
tiling by `num_threads`.
If non-empty, the `threadDimMapping` is added as an attribute to the resulting `scf.foreach_thread`.
0-tile sizes (i.e. tile by the full size of the data) are used to encode
that a dimension is not tiled.

Differential Revision: https://reviews.llvm.org/D129577