Submit disk form on change of dropdown list

Also remove send button as it not necessary anymore.

ogcp/templates/actions/setup.html

@@ -27,16 +27,12 @@
         <tbody data-target="partitons-fieldset" id="setupTable" class="text-center">
                     <tr>
                         <td>
-                            <select form="changeDiskForm" name="disk">
+                            <select form="changeDiskForm" name="disk" onchange="this.form.submit()">
                             {% for disk in disks %}
                                 <option {% if disk == selected_disk %}selected{% endif %}
                                         value="{{ disk }}">{{ disk }}</option>
                             {% endfor %}
                             </select>
-                            <button class="btn btn-dark" form="changeDiskForm" formmethod="get"
-                                    formaction="{{ url_for('action_setup_show') }}">
-                                {{ _('Change disk') }}
-                            </button>
                         </td>
                         {{ form.hidden_tag() }}
                         <td>{{ form.disk_type(class_="form-control") }}</td>