GitLab

* Relax _VALID_URLs
* Improve track metadata extraction

+ Add support for direct http for videos hosted on video.llnw.net
* Check handmade http URLs

Closes #11688

Some codes are borrowed from #7968, which is by @jlhg

Closes #7968

Apparently Niconico now blocks playing without an account

Closes #11170

- Eliminate _transform_rtmp_url
* Generalize triforce mgid extraction
+ [cmt] Add support for full-episodes (closes #11623)

Just a minor fix for openload

- remove check for requires_subscription
- extract more formats
- extract subtitles

method attribute may not be present

These methods are used across codebase with old number of arguments