Split ‘send SMS’ page into two pages

This commit just splits the existing page into two. It doesn’t do any
substantive changes to how the two parts of the page work.

app/templates/views/send-sms.html

@@ -10,34 +10,31 @@
 {% block maincolumn_content %}
   <form method="POST" enctype="multipart/form-data">
 
-        <h1 class="heading-large">Send text messages</h1>
+    <h1 class="heading-large">Send text messages</h1>
 
-    <fieldset class='form-group'>
-      <legend class="heading-medium">1. Choose text message template</legend>
-      {% for template in templates %}
-        {{ sms_message(
-          template.content, name=template.name, input_name='template', input_index=template.id
-        ) }}
-      {% endfor %}
-    </fieldset>
-
-    <h2 class="heading-medium">2. Add recipients</h2>
     {{ banner(
       'You can only send notifications to yourself',
       subhead='Trial mode',
       type='info'
     ) }}
-    <p>
-      Upload a CSV file to add your recipients’ details.
-    </p>
-    <p>
-      You can also <a href="#">download an example CSV</a>.
-    </p>
+
+    {{ sms_message(
+      template.content, name='Preview'
+    ) }}
+
     <p>
       {{textbox(form.file)}}
     </p>
 
-    {{ page_footer("Continue") }}
+    <p>
+      <a href="#">Download an example CSV</a> to test with.
+    </p>
+
+    {{ page_footer(
+      "Continue",
+      back_link=url_for(".choose_sms_template", service_id=service_id),
+      back_link_text="Back to templates"
+    ) }}
 
   </form>
 {% endblock %}