* Added matrix transforms and physical layouts for three typical
configurations.
* Tweaked default keymap to be more immediately useful for ZMK and more
closely resemble the default keymaps of non-ZMK firmware.
* Board-specific Kconfig settings migrated to main shield file, so they
will be exposed to end-users through the setup script.
* Tidied formatting and shortened overlong layer labels.
* Aligned encoder configuration with current standards.
* Corrected default number of RGB LEDs.
* Enabled OLED by default in a less authoritarian way.
