[brightcove] Rename extractor to brightcove legacy

Old embedding approaches are now "Legacy Studio"

youtube_dl/extractor/generic.py

@@ -31,7 +31,7 @@ from ..utils import (
     xpath_text,
 )
 from .brightcove import (
-    BrightcoveIE,
+    BrightcoveLegacyIE,
     BrightcoveInPageEmbedIE,
 )
 from .nbc import NBCSportsVPlayerIE
@@ -1305,7 +1305,7 @@ class GenericIE(InfoExtractor):
                 urlrs, playlist_id=video_id, playlist_title=video_title)
 
         # Look for BrightCove:
-        bc_urls = BrightcoveIE._extract_brightcove_urls(webpage)
+        bc_urls = BrightcoveLegacyIE._extract_brightcove_urls(webpage)
         if bc_urls:
             self.to_screen('Brightcove video detected.')
             entries = [{