generalize logout actor
Currently the logout actor can only be used in (widely-used but) special environments. This is due to the fact that it's assumed, the login URL is being used as the logout location. This will result in a timeout waiting for the #io-ox-login-username
element, which might not be present.
This should be realized an a slightly more general way like waiting for removal of #io-ox-applauncher
element, the last redirect which will always happen, anything but the current way to determine a successful logout.