add placeholder letters page

app/templates/main_nav.html

@@ -50,6 +50,9 @@
   {% if current_user.has_permissions(['view_activity', 'manage_templates', 'manage_api_keys'], admin_override=True, any_=True) %}
     <li><a href="{{ url_for('.choose_template', service_id=current_service.id, template_type='email') }}">Email templates</a></li>
     <li><a href="{{ url_for('.choose_template', service_id=current_service.id, template_type='sms') }}">Text message templates</a></li>
+    {% if current_service.can_send_letters %}
+      <li><a href="{{ url_for('.letters', service_id=current_service.id) }}">Letter templates</a></li>
+    {% endif %}
   {% endif %}
   {% if current_user.has_permissions(['manage_users', 'manage_settings'], admin_override=True) %}
     <li><a href="{{ url_for('.manage_users', service_id=current_service.id) }}">Team members</a></li>

app/templates/views/letters.html

@@ -0,0 +1,19 @@
+{% extends "withnav_template.html" %}
+{% from "components/sms-message.html" import sms_message %}
+{% from "components/email-message.html" import email_message %}
+{% from "components/page-footer.html" import page_footer %}
+{% from "components/file-upload.html" import file_upload %}
+{% from "components/table.html" import list_table, text_field, index_field, index_field_heading %}
+
+{% block page_title %}
+  Upload recipients – GOV.UK Notify
+{% endblock %}
+
+{% block maincolumn_content %}
+
+  <h1 class="heading-large">Letters 📩📨💌📮📜📑👌👌👌</h1>
+  <p>
+    [insert content here]
+  </p>
+
+{% endblock %}

app/templates/views/service-settings.html

@@ -93,6 +93,11 @@
             {{ 'Take service out of research mode' if current_service.research_mode else 'Put into research mode' }}
           </a>
         </li>
+        <li>
+          <a href="{{ url_for('.service_switch_can_send_letters', service_id=current_service.id) }}" class="button">
+            {{ 'Stop sending letters' if current_service.can_send_letters else 'Allow to send letters' }}
+          </a>
+        </li>
       </ul>
 
     {% endif %}