Adds ctrl/cmd+s shortcut to whole application with a noop default

closes #4516
- shortcut for ctrl/cmd+s on application level
Instead of registering a shortcut with no action, globally establish cmd+s as the "save" action. Then just implement a save action on the application route that is a noop. From there, you can remove the save shortcut from any other shortcut route that has it, and just implement the action on controllers that actually do save