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

closes #4516
- shortcut for ctrl/cmd+s on application level
- shortens a syntax for any route that is using 'save' method, shortcuts object doesn't have to be defined at all, only the save action.
Merge pull request #4523 from Gargol/issue-4516

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