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

[sustained]

Per discussion on Discord:

Todo

• 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.