Partial reimplementation of TactilityC GPIO (#469)

* **New Features**
  * Added a GPIO hardware abstraction layer for reading pin levels from applications.
  * Applications can now query the number of available GPIO pins so they can adapt to different devices.
* **Chores**
  * Integrations updated so GPIO capabilities are discoverable and exported to running applications.

TactilityC/Include/tt_hal_gpio.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Logical GPIO pin identifier used by the HAL. Typically maps to the SoC GPIO number. */
+typedef unsigned int GpioPin;
+/** Value indicating that no GPIO pin is used/applicable. */
+#define GPIO_NO_PIN -1
+
+/** Read the current logic level of a pin.
+ * The pin should be configured for input or input/output.
+ * @param[in] pin The pin to read.
+ * @return true if the level is high, false if low. If the pin is invalid, the
+ *         behavior is implementation-defined and may return false.
+ */
+bool tt_hal_gpio_get_level(GpioPin pin);
+
+/** Get the number of GPIO pins available on this platform.
+ * @return The count of valid GPIO pins.
+ */
+int tt_hal_gpio_get_pin_count();
+
+#ifdef __cplusplus
+}
+#endif