[Keyboard] Add rart/rart4x4 with VIA support (#11095)

* Create config.h

* Create info.json

* Create rart4x4.c

* Create rart4x4.h

* Create readme.md

* Create rules.mk

* Create keymap.c

* Create keymap.c

* Rename keyboards/rart/rart4x4/default/keymap.c to keyboards/rart/rart4x4/keymaps/default/keymap.c

* Rename keyboards/rart/rart4x4/via/keymap.c to keyboards/rart/rart4x4/keymaps/via/keymap.c

* Create rules.mk

* Update info.json

* Update keymap.c

* Update rart4x4.h

* Update rules.mk

keyboards/rart/rart4x4/rules.mk

@@ -0,0 +1,25 @@
+# MCU name
+MCU = atmega32u4
+
+# Bootloader selection
+BOOTLOADER = caterina
+
+# Build Options
+#   change yes to no to disable
+#
+BOOTMAGIC_ENABLE = lite     # Virtual DIP switch configuration
+MOUSEKEY_ENABLE = yes       # Mouse keys
+EXTRAKEY_ENABLE = yes       # Audio control and System control
+CONSOLE_ENABLE = no         # Console for debug
+COMMAND_ENABLE = no         # 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 = no       # Enable keyboard backlight functionality
+RGBLIGHT_ENABLE = yes       # Enable keyboard RGB underglow
+BLUETOOTH_ENABLE = no       # Enable Bluetooth
+AUDIO_ENABLE = no           # Audio output
+ENCODER_ENABLE = yes
+
+LAYOUTS = ortho_4x4