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.

keyboards/chimera_ls/info.json

@@ -0,0 +1,13 @@
+{
+  "keyboard_name": "Chimera LS",
+  "url": "",
+  "maintainer": "qmk",
+  "width": 13,
+  "height": 4,
+  "layouts": {
+    "LAYOUT_ortho_4x12": {
+      "key_count": 48,
+      "layout": [{"x":0, "y":0}, {"x":1, "y":0}, {"x":2, "y":0}, {"x":3, "y":0}, {"x":4, "y":0}, {"x":5, "y":0}, {"x":7, "y":0}, {"x":8, "y":0}, {"x":9, "y":0}, {"x":10, "y":0}, {"x":11, "y":0}, {"x":12, "y":0}, {"x":0, "y":1}, {"x":1, "y":1}, {"x":2, "y":1}, {"x":3, "y":1}, {"x":4, "y":1}, {"x":5, "y":1}, {"x":7, "y":1}, {"x":8, "y":1}, {"x":9, "y":1}, {"x":10, "y":1}, {"x":11, "y":1}, {"x":12, "y":1}, {"x":0, "y":2}, {"x":1, "y":2}, {"x":2, "y":2}, {"x":3, "y":2}, {"x":4, "y":2}, {"x":5, "y":2}, {"x":7, "y":2}, {"x":8, "y":2}, {"x":9, "y":2}, {"x":10, "y":2}, {"x":11, "y":2}, {"x":12, "y":2}, {"x":0, "y":3}, {"x":1, "y":3}, {"x":2, "y":3}, {"x":3, "y":3}, {"x":4, "y":3}, {"x":5, "y":3}, {"x":7, "y":3}, {"x":8, "y":3}, {"x":9, "y":3}, {"x":10, "y":3}, {"x":11, "y":3}, {"x":12, "y":3}]
+    }
+  }
+}