feat: notify configured recipients when something is booked

templates/email/booking_created.html.twig

@@ -0,0 +1,26 @@
+{% extends 'email/layout.html.twig' %}
+
+{% block body %}
+    {% set resource = booking.resource %}
+    <h1>Neue Buchung</h1>
+
+    <p>
+        <strong>{{ resource.type.label }} {{ resource.label }}</strong> wurde gebucht.
+    </p>
+
+    <p>
+        Datum: {{ booking.date|format_datetime(pattern: 'EEEE, d. MMMM y') }}
+        <br>
+        Zeit: {{ booking.timeRange }}
+        {% if resource.group %}
+            <br>
+            {{ resource.type.groupLabel }}: {{ resource.group.label }}
+        {% endif %}
+    </p>
+
+    <p>
+        Gebucht von {{ booking.user.name }}
+        <br>
+        {{ booking.user.email }}
+    </p>
+{% endblock %}