Resolve "Add simple course book list"

Closes #256 (closed) Closes #63 (closed)

Screenshots

Frontend todos

• Uhrzeit so wie im Mockup
  • Rechtsbuendig @ZugBahnHof
• Kasten nicht höher als input-feld
• fach und subject strukturierter nebeneinander
• Kursnamen irgendwie hervorheben
• datum gleiche einrückung wie das datum
• datum sollte überschrift sein und prominenter gestaltet
• datum braucht Wochentag
• mittlere spalte linksaligned
• Indikator ob Stundenthema richtig gespeichert wurde (@yuha )
  • when hovering over icon & success: show some fancy success message
  • when hovering over icon & error: show error message
• verify that changes are being tracked using revisions (using a mixin in core creating revisions when mutating) (blocked by AlekSIS-Core!1433 (merged))
• Remove outer card
• Move search, group select, ... into an app bar (see also this)
• Bottom sheet for date select should not be full width of screen (@yuha )
• Statusicon am Anfang der Zeile fehlt (#63 (closed) explains the different stati)

aleksis/apps/alsijil/frontend/components/Coursebook.vue

@@ -13,7 +13,7 @@
           two-line
         >
           <v-list-item-content>
-            <v-list-item-title>{{ day[0] }}</v-list-item-title>
+            <v-list-item-title>{{ day[0].toLocaleString() }}</v-list-item-title>
             <v-list>
               <!-- I know slice copies the array. But show me something better. -->
               <v-list-item v-for="doc in day.slice(1)">
@@ -76,19 +76,20 @@ export default {
     },
   },
   methods: {
+    // => [[dt doc ...] ...]
     groupDocsByDay(docs) {
       const byDay = docs.reduce(
         (byDay, doc) => {
           // This works with dummy. Does actual doc have dateStart instead?
           const day = DateTime.fromISO(doc.datetimeStart).startOf('day');
-          byDay[day] ??= [];
+          byDay[day] ??= [day];
           byDay[day].push(doc);
           return byDay;
         },
         {}
       );
 
-      return Object.keys(byDay).sort().map(key => [key, ...byDay[key]]);
+      return Object.keys(byDay).sort().map(key => byDay[key]);
     },
   },
 };