TactilityC improvements for tt_app_ functions (#192)

- Renamed `tt_app_context_*` to tt_app_*`
- Renamed `AppContextHandle` to `AppHandle`
- Created `tt_app_start()` and `tt_app_start_with_bundle()`

TactilityC/Source/tt_lvgl_toolbar.h

@@ -1,14 +1,14 @@
 #pragma once
 
+#include "tt_app.h"
 #include <lvgl.h>
-#include "tt_app_context.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /** Create a toolbar widget that shows the app name as title */
-lv_obj_t* tt_lvgl_toolbar_create(lv_obj_t* parent, AppContextHandle context);
+lv_obj_t* tt_lvgl_toolbar_create(lv_obj_t* parent, AppHandle context);
 
 /** Create a toolbar widget with the provided title*/
 lv_obj_t* tt_lvgl_toolbar_create_simple(lv_obj_t* parent, const char* title);