[mlir][vector] Allow unroll of contraction in arbitrary order

Adds supprot for vector unroll transformations to unroll in different
orders. For example, the `vector.contract` can be unrolled into a
smaller set of contractions.  There is a choice of how to unroll the
decomposition  based on the traversal order of (dim0, dim1, dim2).
The choice of traversal order can now be specified by a callback which
given by the caller of the transform. For now, only the
`vector.contract`, `vector.transfer_read/transfer_write` operations
support the callback.

Differential Revision: https://reviews.llvm.org/D127004