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

boards/waveshare_s3_touch/lvgl.c

@@ -7,7 +7,7 @@
 bool ws3t_init_lvgl() {
     tt_lvgl_sync_set(&ws3t_display_lock, &ws3t_display_unlock);
 
-    lv_disp_t* display = ws3t_display_create();
+    lv_display_t* display = ws3t_display_create();
     if (display == NULL) {
         return false;
     }