feat: localization (#196)

* Started adding locale translations :)

* Added some more translations

* Working on translating even more pages

* More translations

* Added test default locale retrieval

* replace `intl.formatMessage` with custom `t` hook

* add more translations

* improve title syntax

* add more translations

* translate admin config page

* translated error messages

* add language selecter

* minor fixes

* improve language handling

* add upcoming languages

* add `crowdin.yml`

* run formatter

---------

Co-authored-by: Steve Tautonico <stautonico@gmail.com>

frontend/src/components/account/LanguagePicker.tsx

@@ -0,0 +1,33 @@
+import { Select } from "@mantine/core";
+import { getCookie, setCookie } from "cookies-next";
+import { useState } from "react";
+import { LOCALES } from "../../i18n/locales";
+
+const LanguagePicker = () => {
+  const [selectedLanguage, setSelectedLanguage] = useState(
+    getCookie("language")?.toString()
+  );
+
+  const languages = Object.values(LOCALES).map((locale) => ({
+    value: locale.code,
+    label: locale.name,
+  }));
+  return (
+    <Select
+      value={selectedLanguage}
+      onChange={(value) => {
+        setSelectedLanguage(value ?? "en");
+        setCookie("language", value, {
+          sameSite: "lax",
+          expires: new Date(
+            new Date().setFullYear(new Date().getFullYear() + 1)
+          ),
+        });
+        location.reload();
+      }}
+      data={languages}
+    />
+  );
+};
+
+export default LanguagePicker;