[TrovoLive] Add extractor (partially fix #20)

Only VOD extractor has been implemented

Related: https://github.com/ytdl-org/youtube-dl/issues/26125
Related: https://github.com/blackjack4494/yt-dlc/issues/220

youtube_dlc/utils.py

@@ -4099,7 +4099,8 @@ def strip_jsonp(code):
         r'\g<callback_data>', code)
 
 
-def js_to_json(code):
+def js_to_json(code, vars={}):
+    # vars is a dict of var, val pairs to substitute
     COMMENT_RE = r'/\*(?:(?!\*/).)*?\*/|//[^\n]*'
     SKIP_RE = r'\s*(?:{comment})?\s*'.format(comment=COMMENT_RE)
     INTEGER_TABLE = (
@@ -4128,6 +4129,9 @@ def js_to_json(code):
                     i = int(im.group(1), base)
                     return '"%d":' % i if v.endswith(':') else '%d' % i
 
+            if v in vars:
+                return vars[v]
+
         return '"%s"' % v
 
     return re.sub(r'''(?sx)