refactor: Make all fetchers as an optional dependency group

+ Removing some dead code

scrapling/engines/toolbelt/__init__.py

@@ -5,16 +5,7 @@ from .custom import (
     get_variable_name,
 )
 from .fingerprints import (
-    generate_convincing_referer,
     generate_headers,
     get_os_name,
     __default_useragent__,
 )
-from .navigation import (
-    async_intercept_route,
-    construct_cdp_url,
-    construct_proxy_dict,
-    intercept_route,
-    js_bypass_path,
-)
-from .convertor import ResponseFactory