Clean up old blob revisions before saving the new blob.
Shard files by the least significant digits in their ID.

We never look up at the root of the blob path, it shouldn't be a problem
there are many directories at the top level.
Single level sharing with two digits.
Adding TODO.
Adding more TODOs.
Cleanup blobs on file removals.
Fixing imports.
Use iota at log level enumeration.
Review fixes.
Review fixes.
Merge new namespace layout.