Update to LVGL 9.0.0 (#47)

- Updated LVGL from 8.3 to 9.0 (removed example/docs/demo folders)
- Updated esp_lvgl_port  to current status of the `lvgl9` branch on `esp-bsp`: https://github.com/espressif/esp-bsp/tree/lvgl9
- Updated all boards and drivers
- Removed `libs/lv_drivers` subproject as SDL is now supported by LVGL directly (although keyboard input seems broken)
- Updated `libs/lv_screenshot`
- Fixed the way `tt_statusbar` widget works due to behaviour change in LVGL
- Updated other lvgl code

libs/lvgl/lvgl.pc.in

@@ -5,6 +5,6 @@ libdir=${prefix}/lib
 Name: lvgl
 Description: Light and Versatile Graphics Library
 URL: https://lvgl.io/
-Version: 8.3.11
+Version: 9.0.0
 Cflags: -I${includedir}
 Libs: -L${libdir} -llvgl