Custom emoji & Sticker support (#686)

* Remove comments

* Show custom emoji first in suggestions

* Show global image packs in emoji picker

* Display emoji and sticker in room settings

* Fix some pack not visible in emojiboard

* WIP

* Add/delete/rename images to exisitng packs

* Change pack avatar, name & attribution

* Add checkbox to make pack global

* Bug fix

* Create or delete pack

* Add personal emoji in settings

* Show global pack selector in settings

* Show space emoji in emojiboard

* Send custom emoji reaction as mxc

* Render stickers as stickers

* Fix sticker jump bug

* Fix reaction width

* Fix stretched custom emoji

* Fix sending space emoji in message

* Remove unnessesary comments

* Send user pills

* Fix pill generating regex

* Add support for sending stickers

src/app/molecules/message/Message.scss

@@ -250,7 +250,6 @@
   cursor: pointer;
 
   & .react-emoji {
-    width: 16px;
     height: 16px;
     margin: 2px;
   }