Communicate to the user when an invalid token is used;
Communicate to the user when a valid token which is not owner, admin or editor is used (insufficient permissions); and
Communicate to the user when a valid token is used.
If previously a valid token and organisation were associated, attempting to change the token should warn the user about their local plugin data being cleared.
Related to #3.
If previously a valid token and organisation were associated, attempting to change the token should warn the user about their local plugin data being cleared.