Features to filter videos

[Vayel]

Filtering videos lets us find both videos we like and videos that need more fact-checking. Then, it would be convenient to have these filters:

• Speaker: "Only display videos starring X"
• Title: "Only display videos with X in its title"
• Number of statements: "Order videos by number of statements" (videos with few statements need work)
• Number of statements without source (videos with few sources need work)

[Betree]

Having all the videos for a speaker is kind of supported, you can see all the videos staring a speaker on their pages: https://captainfact.io/s/Emmanuel-Macron

I think 1. and 2. can be solved with a search bar (see #85)

For the rest I agree, it would be great to be able to filter or sort on activity ("Videos that need you" VS "Videos with a lot of participation")