view: expose view_set_maximized() instead of view_restore_to()

view: expose view_set_maximized() instead of view_restore_to()

view_restore_to() (which is just set_maximized() + view_move_resize())
hasn't aged well and doesn't line up with typical usage anymore:

 - it's missing view_set_untiled(), which has to be called separately
 - it always forces view_move_resize() even when that's not needed
 - it doesn't allow un-maximizing only one axis (see next commit)
 - the fullscreen check is unnecessary (already checked in callers)

Eliminate it and just expose view_set_maximized() instead.

No functional change intended in this commit.