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/templates/components/sms-message.html

@@ -1,6 +1,4 @@
-{% macro sms_message(
-  body, recipient=None, name=None, id=None, edit_link=None, from=None
-) %}
+{% macro sms_message(body, recipient=None, name=None, id=None, edit_link=None, from=None) %}
   {% if name %}
     <h3 class="sms-message-name">
       {% if edit_link %}