Keyboard: Chimera LS refactor and Configurator support (#3715)

Keyboard: Chimera LS refactor and Configurator support (#3715)

* Matrix/keymap refactor

- Deleted `KC_KEYMAP` macro
- Renamed `KEYMAP` macro to `LAYOUT_ortho_4x12`
- Default keymap updated to current QMK standards
  - #include QMK_KEYBOARD_H
  - Refactored from `KC_KEYMAP` to `LAYOUT_ortho_4x12` macro
  - `action_get_macro()` deprecated in favor of `process_record_user()`

`rules.mk` *not* updated to include `LAYOUTS = ortho_4x12` because I have no idea if and how that works on a split and/or wireless keyboard.

* readme cleanup: markdown formatting

* Add Configurator support

* added support for ortho_4x12 layout

* Macro and readme updates

Macros updated to use `KC_NO` directly.

Readme updates and cleanup.