Manage tenant information into application - remove dependency on keycloak for rbac

[johnaohara]

The current tight coupling between Keycloak and RBAC for multi-tenancy is hindering adoption in different environments, specifically k8's.

If the tenant information is moved from keycloak into the application, and just use keycloak for IAM, the option to support public IAM providers and custom RBAC providers allows for greater integration with more environments

• [x] https://github.com/Hyperfoil/Horreum/pull/1146
• [x] #1187
• [x] #1188
• [x] #1255
• [x] #1256
• [ ] #1257
• [x] #1258
• [x] #1259
• [x] #1260
• [x] #1261

[johnaohara]

removing from 0.12 milestone, most tasks have been completed, the outstanding issues (https://github.com/Hyperfoil/Horreum/issues/1257) etc will not be completed in for 0.12