Add _33 Keyboard folder (#8543)

* Add _33 Keyboard folder

* Correcting naming convetions and other code convetions

* Removed extra spaces

* fixed layout callbacks to new lower-case versions

* Remove tapping_term, fix RGB pin define. Added blank readme-to be updated.

* initial addition of the readme.md

* Update readme.md for hardware/pcb availability info

* Adding keymap readme

* Info.json added

* Incorporate Drashna's recommended changes

keyboards/underscore33/rules.mk

@@ -0,0 +1,25 @@
+# MCU name
+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
+
+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 = no        # Enable keyboard RGB underglow
+TAP_DANCE_ENABLE = no