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/backend/package.json

@@ -105,7 +105,7 @@
 		"sanitize-html": "2.8.1",
 		"seedrandom": "^3.0.5",
 		"semver": "7.3.8",
-		"sharp": "0.29.3",
+		"sharp": "0.31.3",
 		"speakeasy": "2.0.0",
 		"strict-event-emitter-types": "2.0.0",
 		"stringz": "2.1.0",