[Keyboard] Blackplum a.k.a IMKG68 - new 68% mechanical keyboard (#7122)

* Add blackplum firmware

blackplum firmware

* Delete blackplum.c

* Delete blackplum.h

* Delete config.h

* Delete info.json

* Delete rules.mk

* Delete keymap.c

* Update readme.md

* Delete readme.md

* Add Blackplum

* Add image: blackplum layout

* Update readme.md

* Update readme.md

* remove _WINLCK layer, replaced with custom_keycodes

* change #define LAYOUT_68 to #define LAYOUT_68_ansi

* change  DEBOUNCING_DELAY to DEBOUNCE, remove IS_COMMAND()

* change keyboard_name, maintainer, url, width height

* change some comments

* Update readme

* LAYOUTS = 68_ansi

* update layout_68_ansi

* Change LAYOUT_68 to LAYOUT_68_ansi

Co-Authored-By: fauxpark <fauxpark@gmail.com>

* Fix Bug

* remove extern keymap_config_t keymap_config;

* Update config.h

* Update config.h

* Update config.h

* Update keyboards/blackplum/rules.mk

Co-Authored-By: fauxpark <fauxpark@gmail.com>

* Update rules.mk

* Update rules.mk

* Update readme.md

* Update readme.md

keyboards/blackplum/rules.mk

@@ -0,0 +1,27 @@
+# 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
+BOOTLOADER = qmk-dfu
+
+# Build Options
+#   comment out to disable the options.
+#
+BOOTMAGIC_ENABLE = yes	# 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
+SLEEP_LED_ENABLE = no   # Breathing sleep LED during USB suspend
+NKRO_ENABLE = yes				# USB Nkey Rollover - if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
+BACKLIGHT_ENABLE = no  # Enable keyboard backlight functionality
+AUDIO_ENABLE = no
+RGBLIGHT_ENABLE = yes
+
+LAYOUTS = 68_ansi