add localisation support

currently only en_GB (TODO: dynamic language pack imports)

src/routes/notifications/+page.svelte

@@ -4,6 +4,9 @@
     import { goto } from '$app/navigation';
     import { page } from '$app/stores';
     import Notification from '$lib/ui/Notification.svelte';
+    import Lang from '$lib/lang.js';
+
+    const lang = Lang('en_GB');
 
     if (!$account) goto("/");
 
@@ -31,13 +34,13 @@
 </script>
 
 <header>
-    <h1>Notifications</h1>
+    <h1>{lang.string('navigation.notifications')}</h1>
 </header>
 
 <div class="notifications">
     {#if $notifications.length === 0}
         <div class="loading throb">
-            <span>fetching notifications...</span>
+            <span>{lang.string('notification.fetching')}</span>
         </div>
     {:else}
         {#each $notifications as notif}