Extract the `episode_number` and `upload_date`. Also extract the real `description`.
+ Add support for authentication * Bypass authentication when no credentials provded * Improve extraction robustness
vier.be and vijf.be run on the same CMS and are property of the same company, so the same extractor can be used for both of them.
Now _sort_formats should be called explicitly. _sort_formats has been added to all the necessary places in code. Closes #8051