minor improvements:

- page titles
- favicon
- background logo

frontend/src/routes/notes/Index.svelte

@@ -76,6 +76,10 @@
     loadNotes(loadNotes)
 </script>
 
+<svelte:head>
+    <title>Umbrella – {t('notes')}</title>
+</svelte:head>
+
 <svelte:window {onscroll} />
 {#if error}
 <span class="error">{error}</span>