Merge develop into main (#303)

- `DisplayDevice` improvements related `DisplayDriver`
- Replaced incorrect usage of `spiBusHandle` with `spiHostDevice` in all SPI display devices
- Disabled `DisplayDriver` support for RGB displays for now
- Updated `GraphicsDemo` project for the above changes
- TactilityC improvements:
  - created `tt_hal_device_find()`
  - created `tt_hal_display_*`
  - created `tt_hal_touch_*`
  - created `tt_lvgl_*`
  - export `tt_app_*` calls

TactilityC/Include/tt_lvgl.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** @return true if LVGL is started and active */
+bool tt_lvgl_is_started();
+
+/** Start LVGL and related background services */
+void tt_lvgl_start();
+
+/** Stop LVGL and related background services */
+void tt_lvgl_stop();
+
+#ifdef __cplusplus
+}
+#endif