examples: add basic app metadata to all existing examples.

examples/template.c

@@ -16,6 +16,8 @@ static SDL_Renderer *renderer = NULL;
 /* This function runs once at startup. */
 SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
 {
+    SDL_SetAppMetadata("Example HUMAN READABLE NAME", "1.0", "com.example.CATEGORY-NAME");
+
     if (!SDL_Init(SDL_INIT_VIDEO)) {
         SDL_Log("Couldn't initialize SDL: %s", SDL_GetError());
         return SDL_APP_FAILURE;