[FEATURE] Allow to Update Token in Plugin Form

[X-Tender]

We had a situation lately that the client changed the Password of his IG Account. In this case the Token is no longer valid. To Fix this I had to run the "delete token" Cron Task and then the Client could press the button again to get a fresh token. The problem is that the Tasks can only be called by Admin users in TYPO3, which the client accounts not always have (and want). Could it be possible that event when the Plugin have a valid token, the Button to get a new token is always visible? Or a Button to delete the token vie a Button click in the Plugin.

[einpraegsam]

A button to delete a token would be a nice add on. PR are welcome :)