* Add Scheduled Lives functionality through originallyPublishedAt
Implements #6604 by reusing the originallyPublishedAt field of isLive videos to mark "waiting for live" videos as scheduled at a set time.
* Hide scheduled lives from Browse Videos page
* Add tests for Scheduled Live videos
* Make scheduled lives use a dedicated scheduledAt field in the VideoLive table
* Plan live schedules to evolve in the future
* Use a dedicated table to store live schedules, so we can add multiple
schedules in the future and also add a title, description etc. for a
specific schedule
* Adapt REST API to use an array to store/get live schedules
* Add REST API param so it's the client choice to include or not
scheduled lives
* Export schedules info in user import/export
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Co-authored-by: Chocobozzz <me@florianbigard.com>
* Comments and videos can be automatically tagged using core rules or
watched word lists
* These tags can be used to automatically filter videos and comments
* Introduce a new video comment policy where comments must be approved
first
* Comments may have to be approved if the user auto block them using
core rules or watched word lists
* Implement FEP-5624 to federate reply control policies
