Overview

What this PR does?

Adds the Giphy integration into the Gappein SDK.
Has minimal button UI for launching the GiphyDialogFragment.
How to setup?
Pretty easy, just pass the Giphy key you obtained from https://developers.giphy.com/dashboard/ into the already present
```
Gappein.initialize(this, "KEY")
```
Things need to be looked into:
[x] The Gif is sent with a URL endpoint into the sendMessage() function, but Glide fails to load the gif.
[ ] Probable reason is not being able to fetch a .gif link.