Monitor web token expiration

On a central basis - where the JWT is already validated - monitor the usage per user and add a stgatistics table.

• positive, valid authentication: Update timestamp last_success, null last_expire, null counter_expire
• negative, expired authentication: Update timestamp last_expire, increment counter_expire
• all access: Add user and remote_IP for unique key bundle, so a user has entries per installed server!

Add a view/api readout for all data and add it to some Kuma monitoring via http returncodes