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