AMJ40 Refactor (#11854)

* update keyboard source files

- add license headers (attributed to original keyboard submitter)
- #pragma once include guards
- file template matching
- readme update and template matching

* set sensible default keyboard settings

- enable Bootmagic Lite and Mouse Keys
- disable Console and Command
- remove default keymap's rules.mk file

* remove unnecessary files from default keymap

* refactor default keymap

* add additional layouts/keymaps

* update keyboard readme

- add images and bootloader instructions
- reformat link list

* convert tabs to spaces in default keymap

keyboards/amj40/config.h

@@ -15,8 +15,7 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#ifndef CONFIG_H
-#define CONFIG_H
+#pragma once
 
 #include "config_common.h"
 
@@ -87,5 +86,3 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //#define NO_ACTION_ONESHOT
 //#define NO_ACTION_MACRO
 //#define NO_ACTION_FUNCTION
-
-#endif