Feature: emoji editor (#2411)

* Custom emoji editor: implement backend

This reuses the logo upload code

* Implement emoji edit admin interface

Again reuse base64 logic from the logo upload

* Allow toggling between uploaded and default emojis

* Add route that always serves uploaded emojis

This is needed for the admin emoji interface,
as otherwise the emojis will 404 if custom emojis are disabled

* Fix linter warnings

* Remove custom/uploaded emoji logic

* Reset timer after emoji deletion

* Setup: copy built-in emojis to emoji directory

main.go

@@ -47,6 +47,10 @@ func main() {
 			log.Fatalln("Cannot create data directory", err)
 		}
 	}
+	// Set up emoji directory
+	if err := data.SetupEmojiDirectory(); err != nil {
+		log.Fatalln("Cannot set up emoji directory", err)
+	}
 
 	// Recreate the temp dir
 	if utils.DoesFileExists(config.TempDir) {