Add recently used section to emoji board (#373)

* Add recent section to emoji board

* Add section to emoji board sidebar

* Add emoji limit like element web has

* Ignore custom emojis

* Filter out invalid emojis

* Update heart icon with clock

Co-authored-by: Krishan <33421343+kfiven@users.noreply.github.com>

src/app/organisms/room/RoomViewCmdBar.jsx

@@ -21,6 +21,7 @@ import AsyncSearch from '../../../util/AsyncSearch';
 import Text from '../../atoms/text/Text';
 import ScrollView from '../../atoms/scroll/ScrollView';
 import FollowingMembers from '../../molecules/following-members/FollowingMembers';
+import { addRecentEmoji } from '../emoji-board/recent';
 
 const commands = [{
   name: 'markdown',
@@ -237,6 +238,7 @@ function RoomViewCmdBar({ roomId, roomTimeline, viewEvent }) {
       viewEvent.emit('cmd_fired');
     }
     if (myCmd.prefix === ':') {
+      if (!myCmd.result.mxc) addRecentEmoji(myCmd.result.unicode);
       viewEvent.emit('cmd_fired', {
         replace: myCmd.result.mxc ? `:${myCmd.result.shortcode}: ` : myCmd.result.unicode,
       });