Adding groups logic and restrictions

[AgentScrubbles]

Adds "Groups" as a concept to drop, with the ability to ban certain age ratings from those groups.

This completes the server side for #236 , will need to test the clients.

Flow goes in two ways:

1. If the admin is NOT using OIDC:

• Go to the Users screen
• Scroll down to groups
• Add a new group
• Add users to that group, and then ban age ratings from that group.

2. If the admin IS using OIDC:

• Go to Users screen
• See existing groups
• Ban age ratings from those groups

Both give the ability to ban age ratings from groups if desired, so an admin can create a "kids" group and from there select "ESRB AO" and "ESRB M" ratings which will no longer show up for kids.