fix: Wio Tracker LED on P1.01, move SimpleLed to board layer

Per the Wio Tracker L1 schematic, it has a green LED on P1.01.
Moved SimpleLed from driver/ to board layer (esp32s3.rs and
wio_tracker_l1.rs) since the impl needs HAL-specific Output types.
Removed driver/simple_led.rs — each board layer defines its own.
RAK WisBlock remains LedDriver=() (no user LED on the core module).

src/driver/mod.rs

@@ -1,5 +1,2 @@
 #[cfg(feature = "wio_tracker_l1")]
 pub mod sh1106;
-
-#[cfg(any(feature = "heltec_v3", feature = "heltec_v3_uart", feature = "heltec_v4"))]
-pub mod simple_led;