Login times out

[danbim]

Currently, login timeouts occur on server side no matter if the user is active or inactive. Normally, users should only be logged out after a while of inactivity, therefore the portal should "touch" the users login whenever operations are executed (see itm/testbed-runtime#383).

The WiseGui should as well make sure the user either stays logged in or logs in again on behalf of the user if a timeout occurs (depending on his preference preferrably).

• Detect if logout occurred (e.g. the case if AJAX requests fail with 401 unauthorized). Call /isLoggedIn if this occurs.
• If logout was detected automatically login again if user whishes or present the user with an error messages and a login dialog.