events: allow editing of all used values

Allow to change the date/time and
other relevant values of an event
on creation and after it was created.

app/src/main/res/layout/dialog_notes.xml

@@ -24,4 +24,11 @@
         android:hint="@string/log_notes_dialog_note_hint"
         android:background="@drawable/textview_background"/>
 
+    <TextView
+        android:id="@+id/notes_date_picker"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center"
+        android:layout_marginTop="20dp"/>
+
 </LinearLayout>