add layout for form, consistency with reports

- add buttons at the bottom

Resources/views/Activity/new.html.twig

@@ -23,13 +23,17 @@
 {% block personcontent %}
     <h1>{{ "Activity creation"|trans }}</h1>
 
-    {{ form(form) }}
+    {{ form_start(form) }}
 
-        <ul class="record_actions">
-    <li>
-        <a href="{{ path('chill_activity_activity_list', {'person_id': person.id}) }}">
-            {{ "Back to the list" | trans }}
-        </a>
-    </li>
-</ul>
+    {{ form_widget(form) }}
+        <div class="grid-12 centered sticky-form-buttons">
+            <button class="sc-button green margin-10" type="submit"><i class="fa fa-save"></i> {{ 'Add a new activity'|trans }}</button>
+        </div>
+    {{ form_end(form) }}
+{% endblock %}
+    
+{% block js %}
+<script type="text/javascript">
+    chill.displayAlertWhenLeavingUnsubmittedForm('form[name="{{ form.vars.form.vars.name }}"]', '{{ "You are going to leave a page with unsubmitted data. Are you sure you want to leave ?"|trans }}');
+</script>
 {% endblock %}