[Keymap] Drashna updates for 0.19 (#19175)

* Fix up bastardkb boards since blackpill support is officially added.
  * Check for blackpill version, not elite c.
  * Add checks in chibiOS config since multiple ARM controllers supported.
  * Rework rules.mk for keymaps to better handle arm vs avr support
* Start moving away from `matrix_*_*` functions.
  * `housekeeping_task_*` instead of `matrix_scan_*`
  * `keyboard_(pre|post)_init_*` instead of `matrix_init_*` 
* Add ℂℴmⅈℂ unicode input method.
* Clean up unicode code to be more compact and flexible.
* Remove/move Pro Micro LED commands to userspace and better filter them
* Fixup OLED code
  * Use newer quantum keycode functions/preprocessors rather than manual bit manipulation
  * Make unicode mode render much more compact/simple.
* Make qmk secrets more self contained
* Remove custom implementation of split watchdog

keyboards/bastardkb/charybdis/4x6/keymaps/drashna/rules.mk

@@ -1,34 +1,56 @@
-# MCU name
-MCU = STM32F411
-BOARD = BLACKPILL_STM32_F411
+CUSTOM_UNICODE_ENABLE = no
+CUSTOM_POINTING_DEVICE = no
+CUSTOM_SPLIT_TRANSPORT_SYNC = no
 
-# Bootloader selection
-BOOTLOADER := tinyuf2
+ifeq ($(strip $(KEYBOARD)), bastardkb/charybdis/4x6/blackpill)
+    # MCU name
+    # Bootloader selection
+    BOOTLOADER := tinyuf2
 
-BOOTMAGIC_ENABLE      = yes # Enable Bootmagic Lite
-MOUSEKEY_ENABLE       = yes # Mouse keys
-EXTRAKEY_ENABLE       = yes # Audio control and System control
-CONSOLE_ENABLE        = yes # Console for debug
-COMMAND_ENABLE        = no  # Commands for debug and configuration
-NKRO_ENABLE           = yes # Enable N-Key Rollover
-RGBLIGHT_ENABLE       = no  # Enable keyboard RGB underglow
-AUDIO_ENABLE          = yes # Audio output
-AUDIO_SUPPORTED       = yes # is set to no in kb, needs to be forcibly enabled
+    AUDIO_ENABLE          = yes # Audio output
+    AUDIO_SUPPORTED       = yes # is set to no in kb, needs to be forcibly enabled
+    AUDIO_DRIVER          = pwm_hardware
 
-KEYBOARD_SHARED_EP    = yes
-MOUSE_SHARED_EP       = yes
+    BACKLIGHT_DRIVER      = pwm
 
-EEPROM_DRIVER         = spi
-WS2812_DRIVER         = pwm
-SERIAL_DRIVER         = usart
-AUDIO_DRIVER          = pwm_hardware
-BACKLIGHT_DRIVER      = pwm
+    OVERLOAD_FEATURES = yes
+endif
 
-AUTOCORRECT_ENABLE = yes
-CAPS_WORD_ENABLE      = yes
-SWAP_HANDS_ENABLE     = yes
-TAP_DANCE_ENABLE      = yes
-DEBOUNCE_TYPE         = asym_eager_defer_pk
-WPM_ENABLE            = yes
-LTO_ENABLE            = no
-# OPT                   = 3
+ifeq ($(strip $(KEYBOARD)), bastardkb/charybdis/4x6/v2/stemcell)
+    OVERLOAD_FEATURES = yes
+endif
+ifeq ($(strip $(KEYBOARD)), bastardkb/charybdis/4x6/v2/splinky)
+    OVERLOAD_FEATURES = yes
+endif
+ifeq ($(strip $(MCU)), atmega32u4)
+    LTO_ENABLE = yes
+    BOOTLOADER = qmk-hid
+    BOOTLOADER_SIZE = 512
+endif
+
+ifeq ($(strip $(OVERLOAD_FEATURES)), yes)
+    BOOTMAGIC_ENABLE      = yes # Enable Bootmagic Lite
+    MOUSEKEY_ENABLE       = yes # Mouse keys
+    EXTRAKEY_ENABLE       = yes # Audio control and System control
+    CONSOLE_ENABLE        = yes # Console for debug
+    COMMAND_ENABLE        = no  # Commands for debug and configuration
+    NKRO_ENABLE           = yes # Enable N-Key Rollover
+    RGBLIGHT_ENABLE       = no  # Enable keyboard RGB underglow
+
+    KEYBOARD_SHARED_EP    = yes
+    MOUSE_SHARED_EP       = yes
+
+    AUTOCORRECT_ENABLE    = yes
+    CAPS_WORD_ENABLE      = yes
+    SWAP_HANDS_ENABLE     = yes
+    TAP_DANCE_ENABLE      = yes
+    DEBOUNCE_TYPE         = asym_eager_defer_pk
+    WPM_ENABLE            = yes
+    LTO_ENABLE            = no
+    # OPT                   = 3
+
+    CUSTOM_UNICODE_ENABLE = yes
+    CUSTOM_POINTING_DEVICE = yes
+    CUSTOM_SPLIT_TRANSPORT_SYNC = yes
+
+endif