mapper: Delete map data when deleting a map

Delete map data when deleting a map, instead of only marking it as deleted.

Enhance map functions with a delete_map_data method. Implement it for all
supported versions (v2) and provide stubs for the rest (v0, v1).
mapper: Add support for map renaming.

Support map renaming functionality. It is currently implemented as the
equivalent of a copy and a delete functionality.

The current implementations is problematic, if the user attempts to rename a
mapped volume from the node on which it is mapped. In that case, the rename will
proceed and the mapped volume will experience I/O errors.

The solution to the above problem is not trivial and will be addressed in future
commits.
python: Add support for the rename request
tests: Add tests for the rename functionality
Archipelago: add vlmc rename functionality

Add rename functionality to the vlmc client along with the provided userspace
management tool.