User generated lists

[bitboxer]

A user should be able to create a list and share it with others.

On every Entry I should see an "add to list button" that will show all available lists of a user and offer to create a new list at the bottom of it.

Lists should be public or private. When a list is private it can be shared using a link with token.

A list entry in a user generated list should always link to the exact video. If the video is not there, switch back to the current assigned video of the entry.