[extractor/rai] Rewrite extractors (#5940)

Authored by: nixxo, danog
Closes #5672, closes #6341

Co-authored-by: Daniil Gentili <daniil@daniil.it>

yt_dlp/extractor/_extractors.py

@@ -1548,6 +1548,8 @@ from .radlive import (
     RadLiveSeasonIE,
 )
 from .rai import (
+    RaiIE,
+    RaiCulturaIE,
     RaiPlayIE,
     RaiPlayLiveIE,
     RaiPlayPlaylistIE,
@@ -1556,7 +1558,6 @@ from .rai import (
     RaiPlaySoundPlaylistIE,
     RaiNewsIE,
     RaiSudtirolIE,
-    RaiIE,
 )
 from .raywenderlich import (
     RayWenderlichIE,