add placeholder letters page

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 %}