[extractors] Use new framework for existing embeds (#4307)

`Brightcove` is difficult to migrate because it's subclasses may depend
on the signature of the current functions. So it is left as-is for now

Note: Tests have not been migrated

yt_dlp/extractor/ruutu.py

@@ -135,7 +135,7 @@ class RuutuIE(InfoExtractor):
     _API_BASE = 'https://gatling.nelonenmedia.fi'
 
     @classmethod
-    def _extract_urls(cls, webpage):
+    def _extract_embed_urls(cls, url, webpage):
         # nelonen.fi
         settings = try_call(
             lambda: json.loads(re.search(