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/organisms/settings/Settings.scss

@@ -40,7 +40,8 @@
 .settings-notifications,
 .settings-security__card,
 .settings-security .device-manage,
-.settings-about__card {
+.settings-about__card,
+.settings-emoji__card {
   @extend .settings-window__card;
 }