Fixing RemminaConnectionWindow map/unmap events

The remmina connection windows when in fullscreen is a different object then when is in scrolled mode, therefore the old logic to map and unmap the windows from the plugin it was not working.

Now the events are managed directly from the RCW object and the RemminaProtocolWidget, with an API that can be used by any plugins.

When in multi monitor and fullscreen, this mechanism doesn't work, Therefore, in the plugin itself I catch when we are in multi monitor fullscreen mode And I ignore the event.

This last behavior should be managed directly in the Remmina Protocol Widget (TODO).

Fixes #2475 (closed)

Signed-off-by: Antenore Gatta antenore@simbiosi.org