Ensures reference for image formats and metadata remains intact

Offers a redirect from an old URL that glance docs refer to.
Removes files that are not used.
Renames some files, creates a section for inclusion.

Change-Id: Ic6d4a47ec18a71f359d0eb37cd3e71954e9825b8
Closes-bug: 1244666
Merge "Ensures reference for image formats and metadata remains intact"