Refactor images client for glance v2

*Updated method names and other naming conventions to be more consistent and provide better context
*Updated summary documentation and formating to be consistent throughout
*Replaced id variables with id_
*Replaced file variables with file_
*Replaced id_ with image_id everywhere expect the create_image method for better readability

Change-Id: If205af7672ec1d9ba3448b9c37b0bba1d3996dab
Merge "Refactor images client for glance v2"