Feature request: Application actions & hotkeys

[nytamin]

Currently it is possible to assign hotkeys (keyboard, streamdeck, xkeys etc) to play/stop a certain Part, Group etc..

We should also have a few "Application-level actions" that it should be possible to bind hotkeys to.

Some actions we should implement initially:

• [ ] Play current selected item(s)
• [ ] Stop current selected item(s)
• [ ] Play/Stop current selected item(s)
• [ ] Pause current selected item(s)
• [ ] Cue current selected item(s)
• [ ] Delete current selected item(s)