seeed_xiao_nrf52840_kit improvements (#6930)

* feat: seeed_xiao_nrf52840_kit improvements
- LEDs:
  - Change RGB LED to be active low as it is common anode
  - Remove re-definition of LED_PIN
  - Use red LED to indicate flash writes
  - Use blue LED as user LED (External Notification module)
- GPIO: Re-word unused BUTTON_PIN comment
- Wire: Set I2C pins to match XIAO nRF52840 Sense's LSM6DS3TR IMU
- Battery:
  - Use charge LED to detect charging state
  - Move voltage divider boilerplate out of src/main.cpp and into initVariant()
  - Fix dependencies for above in related XIAO BLE DIY variants

Build tested variants:
- seeed_xiao_nrf52840_kit
- xiao_ble
- seeed-xiao-nrf52840-wio-sx1262

Flashed to and tested on hardware:
- seeed_xiao_nrf52840_kit

Signed-off-by: Andrew Yong <me@ndoo.sg>

* chore(seeed_xiao_nrf52840_kit): Re-order generic GPIO definitions

Signed-off-by: Andrew Yong <me@ndoo.sg>

* chore: Use ADC_CTRL for XIAO nRF52840

Signed-off-by: Andrew Yong <me@ndoo.sg>

---------

Signed-off-by: Andrew Yong <me@ndoo.sg>

src/main.cpp

@@ -482,19 +482,6 @@ void setup()
 
     fsInit();
 
-#if defined(_SEEED_XIAO_NRF52840_SENSE_H_)
-
-    pinMode(CHARGE_LED, INPUT); // sets to detect if charge LED is on or off to see if USB is plugged in
-
-    pinMode(HICHG, OUTPUT);
-    digitalWrite(HICHG, LOW); // 100 mA charging current if set to LOW and 50mA (actually about 20mA) if set to HIGH
-
-    pinMode(BAT_READ, OUTPUT);
-    digitalWrite(BAT_READ, LOW); // This is pin P0_14 = 14 and by pullling low to GND it provices path to read on pin 32 (P0,31)
-                                 // PIN_VBAT the voltage from divider on XIAO board
-
-#endif
-
 #if !MESHTASTIC_EXCLUDE_I2C
 #if defined(I2C_SDA1) && defined(ARCH_RP2040)
     Wire1.setSDA(I2C_SDA1);