feat: Added translations, use locales instead of depending on hardcoded strings. (#65)

## Pull Request Description

Single and hopefully only commit so weblate is up-to-date with last
repository

## Special thanks to the translators 🎉 

@kingu - Noors (Bokmål) (nb_NO)
@alison2033  - Portuguese (Brazil) (pt_BR)
@andreasmolnardev - German (de)
@stanol - Ukrainian (uk)

If I forgot someone let me know!

## Checklist

- [x] If a new package was added, did you ensure it works for all
supported platforms? Is the package also well maintained?
- [x] Did you add localization for any text? If yes, did you sort the
.arb file using ```arb_utils sort <INPUT_FILE>```?
- [x] Check that any changes are related to the issue at hand.

---------

Co-authored-by: PartyDonut <PartyDonut@users.noreply.github.com>

lib/util/local_extension.dart

@@ -1,14 +0,0 @@
-import 'package:flutter/material.dart';
-
-extension LocalExtensions on Locale {
-  String label() {
-    return switch (languageCode) {
-      "nl" => "Nederlands",
-      "zh" => "简体中文",
-      "es" => "Español",
-      "fr" => "Français",
-      "ja" => "日本語 (にほんご)",
-      "en" || _ => "English",
-    };
-  }
-}