[anvato] Improve extraction (closes #12913)

* Promote to regular shortcut based extractor
* Add mcp to access key mapping table
* Add support for embeds extraction
* Add support for anvato embeds in generic extractor

youtube_dl/extractor/extractors.py

@@ -41,6 +41,7 @@ from .alphaporno import AlphaPornoIE
 from .amcnetworks import AMCNetworksIE
 from .animeondemand import AnimeOnDemandIE
 from .anitube import AnitubeIE
+from .anvato import AnvatoIE
 from .anysex import AnySexIE
 from .aol import AolIE
 from .allocine import AllocineIE