Disable HBCI support

It does not work currently and it raises security and legal questions
that need to be answered first.

src/pretix/plugins/banktransfer/templates/pretixplugins/banktransfer/import_form.html

@@ -25,6 +25,7 @@
             </form>
         </div>
     </div>
+    <!--
     <div class="panel panel-default">
         <div class="panel-heading">
             <h3 class="panel-title">{% trans "HBCI import" %}</h3>
@@ -57,4 +58,5 @@
             {% endif %}
         </div>
     </div>
+    -->
 {% endblock %}

src/pretix/plugins/banktransfer/views.py

@@ -38,8 +38,8 @@ class ImportView(EventPermissionRequiredMixin, TemplateView):
     permission = 'can_change_orders'
 
     def post(self, *args, **kwargs):
-        if 'hbci_server' in self.request.POST:
-            return self.process_hbci()
+        # if 'hbci_server' in self.request.POST:
+        #     return self.process_hbci()
 
         if ('file' in self.request.FILES and 'csv' in self.request.FILES.get('file').name.lower()) \
                 or 'amount' in self.request.POST: