[Keyboard] Add cool836A 1_2 (#11467)

* 1st trial on 1_2

* remove keymaps/default/km_default.c

* fix cool836A.h

* fix keymap.c into 3x12

* rename to cool836a (not 'A')

* remove cool836A (not a)

* remove backslashes at keymap.c

Co-authored-by: Ryan <fauxpark@gmail.com>

* update keymap.c (add licence)

* Update keyboards/cool836a/keymaps/default/readme.md

removed "<br>" in line 2

Co-authored-by: Ryan <fauxpark@gmail.com>

* Update keyboards/cool836a/keymaps/default/readme.md

remove "<br>" in line 4

Co-authored-by: Ryan <fauxpark@gmail.com>

* Update keyboards/cool836a/keymaps/default/readme.md

remove "<br>" in line 8

Co-authored-by: Ryan <fauxpark@gmail.com>

* Update keyboards/cool836a/cool836a.h

remove cool836a.h line 30:36

Co-authored-by: Ryan <fauxpark@gmail.com>

Co-authored-by: Ryan <fauxpark@gmail.com>

keyboards/cool836a/keymaps/default/readme.md

@@ -0,0 +1,15 @@
+# m.ki様によるデフォルトキーマップ
+
+[レッドバージョン　ビルドガイド](https://github.com/telzo2000/cool836A/blob/master/buildguide_red.md)で紹介されていたキーマップです。チートシートを見ながらコードに書き写しました。
+
+-------
+## チートシート
+以下、[同ページ](https://github.com/telzo2000/cool836A/blob/master/buildguide_red.md)の画像のコピーを添付します。
++ Layer=0
+![Layer=0](https://github.com/oha-Ohashi/qmk_firmware/blob/images/default_keymap/default_0.png)
++ Layer=1
+![Layer=1](https://github.com/oha-Ohashi/qmk_firmware/blob/images/default_keymap/default_1.png)
++ Layer=2
+![Layer=2](https://github.com/oha-Ohashi/qmk_firmware/blob/images/default_keymap/default_2.png)
++ Layer=3
+![Layer=3](https://github.com/oha-Ohashi/qmk_firmware/blob/images/default_keymap/default_3.png)