Tab5 audio, I2C improvements, UiDensity moved to lvgl-module and cleanup (#506)

- UiDensity moved to lvgl-module
- Deleted tt_hal and tt_hal_gpio (breaks apps, but will fix those right after merging)
- Added I2C 8 bit register operations
- Added device.properties to simulator
- Improved Tab5 hardware init, implement audio
- Add README.md to kernel

Modules/lvgl-module/include/tactility/lvgl_module.h

@@ -16,6 +16,14 @@ extern "C" {
 #include <stdint.h>
 #include <stdbool.h>
 
+/** Affects LVGL widget style */
+enum UiDensity {
+    /** Ideal for very small non-touch screen devices (e.g. Waveshare S3 LCD 1.3") */
+    LVGL_UI_DENSITY_COMPACT,
+    /** Nothing was changed in the LVGL UI/UX */
+    LVGL_UI_DENSITY_DEFAULT
+};
+
 /**
  * @brief The LVGL module instance.
  */
@@ -86,6 +94,14 @@ void lvgl_unlock(void);
  */
 bool lvgl_is_running(void);
 
+/**
+ * @brief Gets the desired UI density for the target hardware.
+ * The density is defined in the `device.properties` of a hardware device.
+ * This setting is read by CMakeLists.txt and passed as a target compile definition of the LVGL module.
+ * @return the UI density
+ */
+enum UiDensity lvgl_get_ui_density(void);
+
 #ifdef __cplusplus
 }
 #endif