Adding a GUI interface to N-Key Panel

[jamesa08]

Describe your feature/proposed changes

Add a GUI interface to the N-Key panel

This will encompass generating execution code via the options selected in the menu. This needs to also sync with features already implemented, and as new items get added, the GUI will adjust accordingly (i.e., a new instrument gets added, and it will also get added to the GUI interface.)

Flowcharts will be added later proposing data flow, and mockups in Paint or Photoshop will be done to mock the interface.
@virtualturtle - I will want your help with mocking the interface layout using Blender's GUI after I create the flow charts.

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Ideas to make this happen:
JSON files to read in already-implemented instruments
I think we will use these to add instruments.

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Additional context
Add any other context or screenshots about the feature request here.