Add Giphy and gfycat to searchable gifs library

[stysk1]

Background

Tenor is currently used to fetch GIFs and it tends to be limited in what it finds sometimes

Solution

Add Giphy and gfycat API endpoints to the fetch process in commands/gif.js.
Decide whether to randomly choose which API for fetching GIFs or do it sequentially.
Failed response from one API endpoint should go to the next API endpoint.