Refactor constants, types and config for glance v2

*Added id to constants module
*Added schemas to types module
*Reordered classes in types to be consistent with rest of images project
*Removed unnecessary configurations due to the refactor from the config module
*Added required configurations due to the refactor to the config file
*Updated summary documentation throughout to be consistent
*Updated ID_RE constant name to ID_REGEX for better readability
*Added admin_user_config

Change-Id: If9cb767eaa633d80044807429b59288073365edb
Merge "Refactor constants, types and config for glance v2"