A little architecture trick here! DTI 2020 authorizes support staff
requests by means of a secret token, instead of user account stuff. And
our support tools still all call DTI 2020 APIs.
So here, we bridge the gap: we copy DTI 2020's support secret to this
app's environment variables (I needed to update
`deploy/files/production.env` and run `bin/deploy:setup` for this!),
then users with the new `support_secret` flag have it added to their
HTML documents in the meta tags. Then, the JS reads the meta tag.
I also fixed an issue in the `deploy/setup.yml` playbook, where I had
temporarily commented some stuff out to skip steps one time, and forgot
to uncomment them after oops lol!
