GitLab

Refs: #4279

Refs: Bug #4276

New format:

/image register Name container:path/to/image

Old format:

/image register Name pithos://user-uuid/container/path/to/image

Now, the old format is also recognized. It is planed to be depricated in a
future version, though

Also, uniformize guides and doc responses for image register

Refs: #4279, 4288

Refs: #4288, #4279

Also, replace page_hold with pydoc.pager

Refs: #4276

Refs: #4276

Refs: #4058

Refs: #4058

Refs: #4058

Refs: #4242

Refs: #4242

Refs: #4232

Conflicts:
	kamaki/cli/commands/snf-astakos.py

Conflicts:
	kamaki/cli/commands/snf-astakos.py