Did some refactor, add YouTube as search variant

bot/handlers/__init__.py

@@ -1,6 +1,7 @@
 from aiogram import Router
 from . import (
     initialize,
+    inline_song,
     inline_default,
     inline_empty,
     on_chosen,
@@ -14,6 +15,7 @@ router.chosen_inline_result.outer_middleware(SaveChosenMiddleware())
 
 router.include_routers(
     initialize.router,
+    inline_song.router,
     inline_default.router,
     inline_empty.router,
     on_chosen.router,