Add keyboard shortcuts to control 'Voice assignment' property

[avvvvve]

We currently have the following shortcut actions that can be used to move certain elements, like notes, from one voice to another when selected:

Now that dynamics and hairpins can be assigned to individual voices, these shortcuts should also work with those elements. Additionally, we can add actions to set the voice to either 'All voices on instrument' or 'All voices on this staff only'.

Tasks

• [ ] Make each of the 'Use voice [#] shortcuts' usable on dynamics on hairpins to control their 'Voice assignment' property
• [ ] Add two new shortcut actions with the following default shortcuts:
  • [ ] 'Use all voices on instrument'
    • Mac: Cmd + Option + 0
    • Windows: Ctrl + Alt + 0
  • [ ] 'Use all voices on this staff only'
    • Mac: Cmd + Option + -
    • Windows: Ctrl + Alt + -
  • These shortcuts will be used to choose from the two nested 'All' options for the 'Voice assignment' property on multi-staff instruments. If the element is on a single-staff instrument, using either of these shortcuts should set 'Voice assignment' to 'All'.

Note: Waiting for sign-off to change the wording of 'Apply to voice' to 'Voice assignment'