Shuffling faves, progressive load for Gif search

Favourites are now loaded, then shuffled before being rendered in the
client.

Gif search with giphy now loads 10 at a time to reduce the load of
trying to render 100 gifs at once, while still allowing the user to load
an additional 10 at a time.

Removed the option for Gifbase and Reply Gif because they don't support
HTTPS.