Following recent similar actions done for entities.
Required at this stage to provider better & cleaner helpers
for common user and permission actions to built out permission testing.
- Required extracting logic into repo.
- Changed some existing creation paths to standardise behaviour.
- Added test to cover new endpoint.
- Added extra test for user delete to test migration.
- Changed how permission errors are thrown to ensure the right status
code can be reported when handled in API.
