Extends management user and group structure (#1268)

* extends user and group structure by introducing fields for issued and integration references

* Add integration checks to group management to prevent groups added by integration.

* Add integration checks to user management to prevent deleting user added by integration.

* Fix broken user update tests

* Initialize all user fields for testing

* Change a serializer option to embedded for IntegrationReference in user and group models

* Add issued field to user api response

* Add IntegrationReference to Group in update groups handler

* Set the default issued field for users in file store

management/server/http/api/openapi.yml

@@ -125,6 +125,10 @@ components:
           description: Is true if this user is blocked. Blocked users can't use the system
           type: boolean
           example: false
+        issued:
+          description: How user was issued by API or Integration
+          type: string
+          example: api
       required:
         - id
         - email