PLT-6763 Implement user access tokens and new roles (server-side) (#6972)

* Implement user access tokens and new roles

* Update config.json

* Add public post permission to apiv3

* Remove old comment

* Fix model unit test

* Updates to store per feedback

* Updates per feedback from CS

config/config.json

@@ -29,6 +29,7 @@
         "EnableInsecureOutgoingConnections": false,
         "EnableMultifactorAuthentication": false,
         "EnforceMultifactorAuthentication": false,
+        "EnableUserAccessTokens": false,
         "AllowCorsFrom": "",
         "SessionLengthWebInDays": 30,
         "SessionLengthMobileInDays": 30,