Admin Section: misc templates corrections and improvments

* reset admin vertical menu custom styles
* disable icons in admin vertical menu
* fix main content positioning in admin section
* fix table appearance in admin crud template
* new scope/center form: move submit button in record_action sticky area
* edit scope/center form: move submit button in record_action sticky area
* improve homogeneity in admin index pages: centers/scopes/users/jobs
* remove centered div old tags

src/Bundle/ChillMainBundle/Resources/views/CRUD/_delete_content.html.twig

@@ -1,4 +1,4 @@
-<div class="{% block crud_content_main_div_class %}col-10 centered{% endblock %}">
+
     {% block crud_content_header %}
         <h1>{{ ('crud.'~crud_name~'.title_delete')|trans({ '%as_string%': entity|chill_entity_render_string }) }}</h1>
     {% endblock crud_content_header %}
@@ -34,4 +34,4 @@
     </ul>
 
     {{ form_end(form) }}
-</div>
+