Piano changes to facilitate training of scales, intervals, building chords etc.

[sustained]

Per discussion on Discord:

Todo

• [x] Allow toggling display of note names entirely.
• [ ] Show proper accidentals depending on key/scale.
• [ ] A mode to only show the note names for notes within the passed:
  • [ ] scale
  • [ ] chord
  • [ ] interval
• [ ] A way to toggle the display of the notes names for the passed scale/chord/interval (for the training modes - i.e. only show after answer).

There are probably more things but this is all I can think of for now.