enhance: Proxy custom emojis to reduce image size and accelerate the frontend (#9431)

* fix(server): /emoji to accept `@.` host expression

* fix(client): use MkEmoji for custom emoji in MkEmojiPicker

* change convertToWebp

* nanka iroiro

* remove

* fix

* nearLosslessは労多くして益少なしなのでやめる

* do not cleanup tmp for development

* update sharp.js to 0.31.3

* mixed: true

* fix MkAutocomplete of 912791b3ab

* clean up

* https://github.com/misskey-dev/misskey/pull/9431#discussion_r1059215943

packages/frontend/src/components/MkEmojiPicker.vue

@@ -81,7 +81,6 @@ import { ref, computed, watch, onMounted } from 'vue';
 import * as Misskey from 'misskey-js';
 import XSection from '@/components/MkEmojiPicker.section.vue';
 import { emojilist, UnicodeEmojiDef, unicodeEmojiCategories as categories } from '@/scripts/emojilist';
-import { getStaticImageUrl } from '@/scripts/get-static-image-url';
 import Ripple from '@/components/MkRipple.vue';
 import * as os from '@/os';
 import { isTouchUsing } from '@/scripts/touch';