Add CLI for V2 image create, update, and upload

Provides command line support for image-create, image-update,
and image-upload using the Glance V2 API. This includes building
help text for create and update based on the image jsonschema
as fetched from the server.

Also fixes bug caused by default warlock patch generation not
matching what Glance expects when updating a core property
which had not originally been set when the image was created.

Related to bp glance-client-v2

Change-Id: I841f9e3d05802f4b794cb6f4849abe03ff0324d9