Project restructuring: add tactility-headless (#55)

- Created `tactility-headless` to support ESP32 firmwares that don't require graphics
- `tactility` subproject now contains both PC and ESP32 code (to avoid having to split up `tactility` and `tactility-headless` into separate projects, which would result in a very complex dependency tree)
- `tactility` subproject is now defined as component for ESP32 and as regular module for PC
- Improvements for dispatcher
- Added `project-structure.puml` to docs
- `Gui` service now depends on `Loader` service instead of the reverse
- Added `statusbar_updater` service for updating Wi-Fi and SD card icons

boards/waveshare_s3_touch/CMakeLists.txt

@@ -1,7 +1,5 @@
 idf_component_register(
     SRC_DIRS "."
     INCLUDE_DIRS "."
-    REQUIRES lvgl esp_lcd esp_lcd_touch_gt911
+    REQUIRES tactility lvgl esp_lcd esp_lcd_touch_gt911
 )
-
-target_link_libraries(${COMPONENT_LIB} ${IDF_TARGET_NAME} tactility)

boards/waveshare_s3_touch/waveshare_s3_touch.c

@@ -9,5 +9,5 @@ const HardwareConfig waveshare_s3_touch = {
     .display = {
         .set_backlight_duty = NULL // TODO: This requires implementing the CH422G IO expander
     },
-    .init_lvgl = &ws3t_init_lvgl
+    .init_graphics = &ws3t_init_lvgl
 };