feat(developer): emit .kvks and .keyman-touch-layout files and corresponding binaries in kmc 🙀

[mcdurdin]

brain dump from discussion earlier this week.

kmc vs kmldmlc: see #7237

• kmldmlc must generate .kvks (#5077) and .keyman-touch-layout (#5078).
• could also generate binary .kvk and 'compiled' touch layout JSON?
  • ideally kmldmlc generates these too
• questions on generating keyboard.js as well!
  • ideally kmldmlc generates this as well

Subquestion:

• do we include this data in kmxplus?
• Would mean separate .kvk file wouldn't be needed, one day in the future.
• Would be equivalent to xml data, not an encapsulated .kvk file or .keyman-touch-layout
• Would look a lot like LDML layerMaps (with displayMap applied).
• Using synthesized vkeys for touch layouts (not ids)

[mcdurdin]

.keyman-touch-layout is 18.0. .kvk is done.