Devicetree DTS and YAML format improvements (#492)

* **DevicetreeCompiler**
  * Binding properties now support default values.
  * Compiler returns meaningful exit codes and reports errors more clearly.
  * Stronger validation of device configurations with unified error handling.
  * Added integration tests and a dedicated Devicetree test workflow.

* **Changes**
  * Platform binding schemas updated: some fields made required, others gained explicit defaults.
  * Many device-tree files simplified by removing unused/placeholder pin and transfer-size entries.

* **Documentation**
  * Removed several outdated TODO items.

Platforms/PlatformEsp32/Bindings/espressif,esp32-uart.yaml

@@ -21,7 +21,9 @@ properties:
     description: RX pin
   pin-cts:
     type: int
+    default: GPIO_PIN_NONE
     description: CTS pin
   pin-rts:
     type: int
+    default: GPIO_PIN_NONE
     description: RTS pin