Add customization to discover tab

It would be useful to have more control over the discover tab. Some ideas:

- Ability to choose source for popular/trending (Ombi? IMDB? Trakt? Rotten Tomatoes?)
- More possible rows (recently available, recently requested, new releases, genre/actor/seasonal, award winners, collections/tags)
- Ability to filter out content based on additional criteria (content rating, country, language, ratings)
- Ability to hide select content