[New Environment Setup] Add SSL setup instructions #3733
Description
There are existing instructions for setting up SSL, but they can be simplified if the site is initially setup with a proper domain name (PR here), and if letsencrypt_cchq_ssl: yes is set in proxy.yml.
The remaining steps from ssl.md are quite minimal and can be duplicated in-line in new_environment.md.
This new workflow will of course need to be tested.