Draft: return of melodic demo

menu entry is now "mono synth"

how to: (app button down to switch mode)

• main mode:
  • all 10 petals to play notes
  • left/right on app button to shift around scale
• synth config mode:
  • top petals play notes, same as in main mode
  • bottom petals except for 5 are sliders to change parameters
  • left/right on app button to switch between parameter page
  • petal 5 may scroll thru modulator config (osc, filter) or toggle drone mode (env) or do nothing atm (lfo).

todo b4 merge:

• add more sources to modulation matrix (positional captouch, gyro, (someday badge link cv but not now probably))
• save/load state
• improve oscillator, we're bad at this synth biz soo it's taking a while to figure it out :3
• scale config
• partial redraw -> more frames
• make LEDs prettier
• write proper docs