WIP: Key selector redesign

[algernon]

This is a draft PR, a heavy work in progress. The goal is to replace our current key selector (and keymap database) with something that's easier to work with, for both users and developers.

Goals:

• Allow users to select keys with considerably less clicks.
• Allow us to support multiple languages and layouts (us-qwerty, hu-qwertz, bépo, stb).

Builds:

• Linux x86-64
• Linux arm64
• macOS
• Windows

Current status:

TODO

Must have

• Make OneShot keys available on the selector
• Move the layout dropdown from the keyboard settings to the editor - postponed due to technical difficulties
• Save and remember the layout chosen
• On start, load the saved keyboard layout.
• Sort the available layouts alphabetically in the dropdown
• Finish up modifier+key and DualUse support
  • Modifier+key, and combinations of it, should be supported for all base keys.
  • DualUse should be in the DB
  • DualUse should be wired up on the selector
• Migrate the rest of the old database to the new, so all known keys display properly
  • Leader
  • LED keys
  • Macros
  • Mouse Control
  • OneShot
  • SpaceCadet
  • Steno
  • TapDance
• Add a direct keycode editor widget for unknown keycodes
• Update the rest of the keyboards to work with the new system
  • Keyboardio Atreus
  • Keyboardio Model01
  • Dygma Raise - postponed
  • ErgoDox
  • KBDFans KBD4x
  • OLKB Planck
  • Splitography
  • Technomancy's Atreus
• Figure out how to display all 5 modifiers and the DualUse switch, preferably without increasing the height of the selector.
  • Add a new entry to the vertical tab, and use a similar method we use for ModifierKeyboard104.

Nice to have

• Make the key selector Slide resizable via dragging. (See here for some hints)
• As part of the above, the keymap widget should be independently scrollable, and the selector should slide over it from the bottom.
• Rebuild the database on top of the new foundation, including all the keys we had in the old db.
• Make the text more readable. We can do this by showing only a single label with bigger font size (instead of 1-3 labels)
• Possibly rearrange the keyboard a bit to save vertical space:
  • Esc would move before the backtick, and we'd push the rest of the row to a "Function row" tab
• Support vertical text (for numpad Enter, for example) - this affects the device keymaps too, those should support it too
• Figure out ideal text lengths, and short names for our keys that have longer names.
• Add a generic keymap formatter that the selector and the keymap can both use
  • This should turn {label: {name: "ShiftToLayer", target: 1}} to {label: {top: "ShiftToLayer", bottom: "1"}} or something along those lines

[algernon]

I'm going to close this one, because the scope has increased substantially since, and I feel it's better to do a separate PR for that. I'll open that later today or tomorrow, once I cleaned up the branch a bit.