[Keyboard] Add ArcticPCB pre-Alpha support (#8479)

* Add initial ArcticPCB support

* Added README

* Solve info.json comma issue

* Apply suggestions from noroadsleft code review

Use the LAYOUT_60_tsangan_hhkb Community Layout

* Apply suggestions from tzarc

* Add license header to arctic.c, arctic.h and config.h

* Remove redundant tsangan keymap

* Remove tsangan compilation suggestion from readme

keyboards/acheron/arctic/rules.mk

@@ -0,0 +1,22 @@
+# MCU name
+MCU = STM32F072
+
+# Build Options
+#   change yes to no to disable
+#
+BOOTMAGIC_ENABLE = yes      # Virtual DIP switch configuration
+MOUSEKEY_ENABLE = yes       # 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 = no       # Enable keyboard backlight functionality
+RGBLIGHT_ENABLE = no        # Enable keyboard RGB underglow
+BLUETOOTH_ENABLE = no       # Enable Bluetooth with the Adafruit EZ-Key HID
+AUDIO_ENABLE = no           # Audio output on port C6
+
+# Enter lower-power sleep mode when on the ChibiOS idle thread
+OPT_DEFS += -DCORTEX_ENABLE_WFI_IDLE=TRUE