Persistent sessions are a problem for the last login date

Summary

Since !1585 (merged) people can stay logged in for a long time. The 'last login' timestamp is however only updated on login and therefore not really valid in any case. Some functions depend on that value and might assume that users are not active anymore even though they are.

Possible fixes

Maybe the nightly maintenance script could check all open sessions and update the login date for those users. Another option might be to use the websocket from the message API.