admin: add CancelReason admin

src/Bundle/ChillCalendarBundle/Resources/views/CancelReason/edit.html.twig

@@ -0,0 +1,11 @@
+{% extends '@ChillMain/CRUD/Admin/index.html.twig' %}
+
+{% block title %}
+    {% include('@ChillMain/CRUD/_edit_title.html.twig') %}
+{% endblock %}
+
+{% block admin_content %}
+    {% embed '@ChillMain/CRUD/_edit_content.html.twig' %}
+        {% block content_form_actions_save_and_show %}{% endblock %}
+    {% endembed %}
+{% endblock admin_content %}