Closes #5892: Introduce SiteGroup model (#5937)

* Initial work on #5892

* Add site group selection to object edit forms

* Add documentation for site groups

* Changelog for #5892

* Finish application of site groups to config context

netbox/templates/extras/configcontext.html

@@ -66,6 +66,20 @@
                             {% endif %}
                         </td>
                     </tr>
+                    <tr>
+                        <td>Site Groups</td>
+                        <td>
+                            {% if object.site_groups.all %}
+                                <ul>
+                                    {% for sitegroup in object.site_groups.all %}
+                                        <li><a href="{{ sitegroup.get_absolute_url }}">{{ sitegroup }}</a></li>
+                                    {% endfor %}
+                                </ul>
+                            {% else %}
+                                <span class="text-muted">None</span>
+                            {% endif %}
+                        </td>
+                    </tr>
                     <tr>
                         <td>Sites</td>
                         <td>

netbox/templates/extras/configcontext_edit.html

@@ -15,6 +15,7 @@
         <div class="panel-heading"><strong>Assignment</strong></div>
         <div class="panel-body">
             {% render_field form.regions %}
+            {% render_field form.site_groups %}
             {% render_field form.sites %}
             {% render_field form.roles %}
             {% render_field form.platforms %}