Note that even though the sparse runtime support lib always uses SoA
storage for COO storage (and provides correct codegen by means of views
into this storage), in some rare cases we need the true physical SoA
storage as a coordinate buffer. This PR provides that functionality by
means of a (costly) coordinate buffer call.

Since this is currently only used for testing/debugging by means of the
sparse_tensor.print method, this solution is acceptable. If we ever want
a performing version of this, we should truly support AoS storage of COO
in addition to the SoA used right now.

remove some obsoleted APIs from the library that have been fully
replaced with actual direct IR codegen

1. Add parsing methods for block[n, m].
2. Encode n and m with the newly extended 64-bit LevelType enum.
3. Update 2:4 methods names/comments to n:m.

Fixes a bug that appended values after insertion completed. Also slight
optimization by avoiding all-Dense computation for every lexInsert call

The "Dim" prefix is a legacy left-over that no longer makes sense, since
we have a very strict "Dimension" vs. "Level" definition for sparse
tensor types and their storage.

This adds library support for these two new level formats.

This enables reading block sparse from file using libgen! (and soon also
direct IR codegen)

This cleans up all external entry points that will have to deal with
non-permutations, making any subsequent refactoring much more local to
the lib files.