Make the flow of using templates better

For users who:
- want to send messages from a template
- want to edit templates

For developers:
- who need to get the ID of a template

This commit mainly cleans up the choose template page so there are less
options, and the options that are there are less wordy.

This means:
- moving ‘send yourself a test’ onto the send messages page, and making
  it button
- stripping a lot of stuff out of the ‘send from API’ page, so it’s more
  obvious what the template ID is

app/main/views/send.py

@@ -183,19 +183,16 @@ def send_message_to_self(service_id, template_id):
 @user_has_permissions('manage_api_keys')
 def send_from_api(service_id, template_id):
     template = Template(
-        service_api_client.get_service_template(service_id, template_id)['data']
+        service_api_client.get_service_template(service_id, template_id)['data'],
+        prefix=current_service['name']
     )
-    payload = {
-        "to": current_user.mobile_number,
-        "template": template.id,
-        "personalisation": {
-            placeholder: "{} 1".format(placeholder) for placeholder in template.placeholders
-        }
+    personalisation = {
+        placeholder: "..." for placeholder in template.placeholders
     }
     return render_template(
         'views/send-from-api.html',
         template=template,
-        payload=json.dumps(payload, indent=4)
+        personalisation=json.dumps(personalisation, indent=4) if personalisation else None
     )