Refs #5217: Merging roles branch to master.

This merges the following converted entities to master:

Lifecycle Environments
Subscriptions
Activation Keys
Products and Repositories
Sync Functionality
Sync Plans
Content Views (except for promote)
Content Hosts
GPG Keys

For each of the above entities, Foreman based permissions can be used to create filters that are then added to roles. This management is done through the normal Foreman roles/filters interface. 

Testing of these entities can be done by creating a new user and assigning role(s) with various Katello entity permissions and attempting to perform functions through the API or UI. 

Note the following:

 - Not all UI actions are hidden/shown based upon current permissions but the server will deny
 - Not all Katello entities are converted (host collections, content and content search and environment locking are being finish up and targeted for master)
 - Super admin users will still have all functionality available to them