virt-viewer-window: Allow to resize window to any size
    
    The function virt_viewer_window_resize restricts window to be bigger
    than a client's screen. It avoids extending the window to more client's
    screens, it causes changes of the zoom level if the guest does not fit
    into a screen.
    
    Lets remove virt_viewer_window_resize (its behaviour was introduced
    by the commit 6acb3856b6d8007752388f22f97aa8aaffdb7a5e). It will let
    the window managers to handle resizing of the window.
    
    Resolves:
    https://bugzilla.redhat.com/show_bug.cgi?id=1221501
    https://bugzilla.redhat.com/show_bug.cgi?id=1205804