CORE-232: create 'user' resource type

[davidangb]

Ticket: https://broadworkbench.atlassian.net/browse/CORE-232

What:

Create a new user resource type for the sole purpose of being able to query for support permissions on the resource_type_admin/user resource.

As of this writing, we don't expect anything to create user resources themselves.

This PR is an offshoot of #1617 - see comment threads in that other PR for context.

---

PR checklist

• I've followed the instructions if I've made any changes to the API, especially if they're breaking changes
• I've filled out the Security Risk Assessment (requires Broad Internal network access) and attached the result to the JIRA ticket

[dvoet]

Do we care that anyone can create user resources? They don't do anything.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud