added support for douyin

- full support for douyin (no watermark)
- fixed up some tiktok stuff in the module

src/modules/config.js

@@ -9,6 +9,7 @@ version = packageJson.version,
 streamLifespan = config.streamLifespan,
 maxVideoDuration = config.maxVideoDuration,
 genericUserAgent = config.genericUserAgent,
+mobileUserAgent = config.mobileUserAgent,
 repo = packageJson["bugs"]["url"].replace('/issues', ''),
 authorInfo = config.authorInfo,
 supportedLanguages = config.supportedLanguages,