Add HELPDESK_ENABLE_ATTACHMENTS setting and make it show/hide attachment related UI

Default setting is false. This is not backward compatible.
The rationale is: attachments contain most likely sensitive information.
By default they are served without access control.  Currently there is
no simple feature to configure access control.  To avoid unintentional
disclosure attachments should be an opt in: you have been warned.

helpdesk/forms.py

@@ -239,6 +239,7 @@ class AbstractTicketForm(CustomFieldMixin, forms.Form):
         label=_('Due on'),
     )
 
+    if helpdesk_settings.HELPDESK_ENABLE_ATTACHMENTS:
         attachment = forms.FileField(
             widget=forms.FileInput(attrs={'class': 'form-control-file'}),
             required=False,

helpdesk/settings.py

@@ -56,6 +56,11 @@ HELPDESK_STAFF_VIEW_PROTECTOR = getattr(settings,
                                          'HELPDESK_STAFF_VIEW_PROTECTOR',
                                          lambda _: None)
 
+# Enable ticket and Email attachments
+HELPDESK_ENABLE_ATTACHMENTS = getattr(settings,
+                                      'HELPDESK_ENABLE_ATTACHMENTS',
+                                      False)
+
 # Enable the Dependencies field on ticket view
 HELPDESK_ENABLE_DEPENDENCIES_ON_TICKET = getattr(settings,
                                                  'HELPDESK_ENABLE_DEPENDENCIES_ON_TICKET',

helpdesk/templates/helpdesk/public_view_ticket.html

@@ -123,6 +123,7 @@
 
     </dl>
         
+{% if helpdesk_settings.HELPDESK_ENABLE_ATTACHMENTS %}
 <p id='ShowFileUploadPara'><button class="btn btn-warning btn-sm"
     id='ShowFileUpload' onclick="$('#FileUpload')[0].style.display='block';return false;" >{% trans "Attach File(s) &raquo;" %}</button></p>
 
@@ -140,7 +141,7 @@
     </dl>
 
 </div>
-
+{% endif %}
 </fieldset>
 
 <button class="btn btn-primary btn-lg" style="margin-bottom:10px" type='submit'>{% trans "Update This Ticket" %}</button>

helpdesk/templates/helpdesk/ticket.html

@@ -54,6 +54,7 @@
                                     <li>{% blocktrans with change.field as field and change.old_value as old_value and change.new_value as new_value %}Changed {{ field }} from {{ old_value }} to {{ new_value }}.{% endblocktrans %}</li>
                                     {% if forloop.last %}</ul></div>{% endif %}
                                 {% endfor %}
+                                {% if helpdesk_settings.HELPDESK_ENABLE_ATTACHMENTS %}
                                     {% for attachment in followup.followupattachment_set.all %}{% if forloop.first %}{% trans "Attachments" %}:<div class='attachments'><ul>{% endif %}
                                     <li><a href='{{ attachment.file.url }}'>{{ attachment.filename }}</a> ({{ attachment.mime_type }}, {{ attachment.size|filesizeformat }})
                                         {% if followup.user and request.user == followup.user %}
@@ -62,6 +63,7 @@
                                     </li>
                                         {% if forloop.last %}</ul></div>{% endif %}
                                     {% endfor %}
+                                {% endif %}
                             </p>
                             <!--- ugly long test to suppress the following if it will be empty, to save vertical space -->
                             {% with possible=helpdesk_settings.HELPDESK_SHOW_EDIT_BUTTON_FOLLOW_UP %}
@@ -197,7 +199,9 @@
             </div>
         {% endif %}
 
+        {% if helpdesk_settings.HELPDESK_ENABLE_ATTACHMENTS %}
         <p id='ShowFileUploadPara'><button type="button" class="btn btn-warning btn-sm" id='ShowFileUpload'>{% trans "Attach File(s) &raquo;" %}</button></p>
+        {% endif %}
 
         <div id='FileUpload' style='display: none;'>
 

helpdesk/templates/helpdesk/ticket_desc_table.html

@@ -150,6 +150,7 @@
                             <td> <a href ="{{ticket.kbitem.query_url}}"> {{ticket.kbitem}} </a> </td>
                         </tr>
 		    {% endif %}
+		    {% if helpdesk_settings.HELPDESK_ENABLE_ATTACHMENTS %}
                     <tr>
                         <th class="table-active">{% trans "Attachments" %}</th>
                         <td colspan="3">
@@ -171,6 +172,7 @@
                             </ul>
                         </td>
                     </tr>
+                    {% endif %}
                     <tr>
                         <th class="table-active">{% trans "Checklists" %}</th>
                         <td colspan="3">