[mlir][sparse] implement simple reshaping (expand/collapse)

The revision makes a start with implementing expand/collapse reshaping
for sparse tensors. When either source or destination is sparse, but
other is dense, the "cheap" dense reshape can be used prior to converting
from or to a sparse tensor.

Note1
sparse to sparse reshaping is still TBD.

Note2
in the long run, we may want to implement a "view" into a sparse tensor so that the operation remains cheap and does not require data shuffling

Reviewed By: wrengr

Differential Revision: https://reviews.llvm.org/D129031