Refactor get_by_id to match get_by_uuid

Also set mysql_traditional_mode where it was not set

Change-Id: I98365e5a1912488152a6b07d92a54ab3a72fe053
Extend RequestContext class

This patch adds new attributes into RequestContext class
 * user_name - user name from authentication information
 * roles - a list of roles for user
 * service_catalog - a list of service endpoints

Change-Id: Id1bcbf5fb0a0286d5e14a96e4ed222946bc2888e
Merge "Refactor get_by_id to match get_by_uuid"
Merge "Extend RequestContext class"