AMJ60 Refactor (#13530)

* rename LAYOUT to LAYOUT_all

* refactor default keymap

- add license header
- use layer_names enum
- use LAYOUT_all macro
- update keymap to be more generic
- use QMK-native keycode aliases

* info.json: human-friendly formatting

* convert LAYOUT_iso into a proper LAYOUT_60_iso

* LAYOUT_all bugfix

In the physical sense, position k3d is to the left of k3c.

* rework LAYOUT_max into LAYOUT_60_ansi_split_bs_rshift

* remove LAYOUT_iso_splitrshift and iso_split_rshift keymap

* rework LAYOUT_hhkb into LAYOUT_60_hhkb

* amj60.h cleanup

- add license header
- use #pragma once include guard
- concatenate layout block comments
- remove unnecessary function headers

* add license header to amj60.c

* align config.h to QMK template

* align rules.mk to QMK template

* enable Community Layout support

* modernize readme.md

- add PCB image
- convert keyboard data to list
- add flashing and bootloader instructions
- update Docs links

keyboards/amj60/rules.mk

@@ -2,29 +2,23 @@
 MCU = atmega32u4
 
 # Bootloader selection
-#   Teensy       halfkay
-#   Pro Micro    caterina
-#   Atmel DFU    atmel-dfu
-#   LUFA DFU     lufa-dfu
-#   QMK DFU      qmk-dfu
-#   ATmega32A    bootloadHID
-#   ATmega328P   USBasp
 BOOTLOADER = atmel-dfu
 
 # Build Options
-#   comment out to disable the options.
+#   change yes to no to disable
 #
-BOOTMAGIC_ENABLE = no  # Virtual DIP switch configuration
-MOUSEKEY_ENABLE  = no  # Mouse keys
-EXTRAKEY_ENABLE  = yes # Audio control and System control
-CONSOLE_ENABLE   = yes # Console for debug
-COMMAND_ENABLE   = yes # Commands for debug and configuration
-NKRO_ENABLE      = yes # USB Nkey Rollover - if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
-RGBLIGHT_ENABLE  = yes # Enable keyboard underlight functionality
-BACKLIGHT_ENABLE = yes # Enable keyboard backlight functionality
-MIDI_ENABLE      = no  # MIDI controls
-AUDIO_ENABLE     = no
-UNICODE_ENABLE   = no  # Unicode
-BLUETOOTH_ENABLE = no  # Enable Bluetooth with the Adafruit EZ-Key HID
+BOOTMAGIC_ENABLE = no       # Virtual DIP switch configuration
+MOUSEKEY_ENABLE = no        # Mouse keys
+EXTRAKEY_ENABLE = yes       # Audio control and System control
+CONSOLE_ENABLE = yes        # Console for debug
+COMMAND_ENABLE = yes        # Commands for debug and configuration
+# Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
+SLEEP_LED_ENABLE = no       # Breathing sleep LED during USB suspend
+# if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
+NKRO_ENABLE = yes           # USB Nkey Rollover
+BACKLIGHT_ENABLE = yes      # Enable keyboard backlight functionality
+RGBLIGHT_ENABLE = yes       # Enable keyboard RGB underglow
+BLUETOOTH_ENABLE = no       # Enable Bluetooth
+AUDIO_ENABLE = no           # Audio output
 
-LAYOUTS = 60_ansi
+LAYOUTS = 60_ansi 60_hhkb 60_iso 60_ansi_split_bs_rshift