add recently used emojis panel to emoji picker (#283)

~~(not intended for merging yet, just submitting this for preliminary review and discussion)~~

this patch adds a tab with recently used emojis to the emoji picker: https://akko.lain.gay/notice/ASoGCtyoiXbYPJjqpk

there's a couple of things i'm ~~still trying to work out~~ not totally happy with and i'd appreciate any feedback on them:

* the recentEmojis getter is called very frequently and has to do a possibly somewhat expensive lookup of emoji objects by their `displayName` each time, which i'm not sure is ideal
* ~~emoji reactions on posts added through the picker are picked up by the recentEmojis module, but clicks on existing emoji reactions are not, because `addReaction` in `react_button.js` only currently receives the replacement and not the full emoji object (if there even is one wherever that method is called from)~~ this works now and does the same stupid full search of all emojis by their name which i guess is less bad because this only happens when you hit a reaction emoji button that already existed

Reviewed-on: https://akkoma.dev/AkkomaGang/akkoma-fe/pulls/283
Co-authored-by: flisk <akkomadev.mvch71fq@flisk.xyz>
Co-committed-by: flisk <akkomadev.mvch71fq@flisk.xyz>

src/lib/persisted_state.js

@@ -19,7 +19,8 @@ const saveImmedeatelyActions = [
   'setOption',
   'setClientData',
   'setToken',
-  'clearToken'
+  'clearToken',
+  'emojiUsed',
 ]
 
 const defaultStorage = (() => {