This changes the site to run on Debian 10 instead of Ubuntu 16.04. It
also fully converts the previous Salt setup to use Ansible instead.
Most of this was a relatively straightforward conversion, and it should
be very close to equivalent. One notable difference is that I removed
the setup for the "monitoring" server, since I wasn't confident that the
way of setting up self-hosted Sentry and Grafana was working any more.
I'll look to re-add that at some point, but it's not urgent.
These were set up to redirect the original locations of the development
pages to their new locations inside the instructions folder, but can't
be used any more now that we're creating a development folder.
Previously, this was set as "same-origin" which will only send a
referrer to Tildes itself. This changes so that it will continue sending
the full referrer to Tildes, but will send only the domain to external
sites if they use HTTPS (and no referer to HTTP ones).
This can be useful because there are often situations where an article
author sees traffic coming from a site and will come to check it out and
be able to participate in the discussion.
Deimos