fix: support md5 url rewriting for proxied instances

depends on public_facing_url instead of perceived request url (which
can, and will be different for proxied instances)

views.py

@@ -99,10 +99,11 @@ def videoplaybackProxy():
 			return Response(json.dumps({"error": "Videoplayback request not cached or expired."}), mimetype="application/json", status=404)
 		return redirect(ythdd_globals.general_cache["hashed_videoplayback"][params["md5"]]["original_url"])
 	else:
-		md5sum = hashlib.md5(request.url.encode("utf-8")).hexdigest()
+		public_url = request.url
+		public_url = ythdd_globals.config["general"]["public_facing_url"] + public_url[public_url.rfind("videoplayback"):]
+		md5sum = hashlib.md5(public_url.encode("utf-8")).hexdigest()
 		ythdd_globals.general_cache["hashed_videoplayback"][md5sum] = {"original_url": request.url}
 
-
 	# reconstruct the url
 	# first attempt: from host param
 	host = params.get('host')