[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/3x5/keymaps/drashna/keymap.c

@@ -83,24 +83,28 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
     ),
 };
 
-void matrix_init_keyemap(void) { setPinInputHigh(A0); }
+#if defined(KEYBOARD_bastardkb_charybdis_3x5_blackpill)
+void keyboard_pre_init_keymap(void) {
+    setPinInputHigh(A0);
+}
 
-void matrix_scan_keymap(void) {
+void housekeeping_task_keymap(void) {
     if (!readPin(A0)) {
         reset_keyboard();
     }
 }
 
-#ifdef USB_VBUS_PIN
+#    ifdef USB_VBUS_PIN
 bool usb_vbus_state(void) {
     setPinInputLow(USB_VBUS_PIN);
     wait_us(5);
     return readPin(USB_VBUS_PIN);
 }
-#endif
+#    endif
 
 void matrix_output_unselect_delay(uint8_t line, bool key_pressed) {
     for (int32_t i = 0; i < 40; i++) {
         __asm__ volatile("nop" ::: "memory");
     }
 }
+#endif