Reconcile with live instance, rewrite CI

This includes !17 (merged), plus the changes from the live instance on emeril.fd.o, which uses a virtualenv when invoking parsemail.py, special-cases igt vs. intel-gfx/dri-devel, and adds reCAPTCHA support for registration. The reCAPTCHA support has been fixed to no longer break the tests.

The container build has also been split in two: one builds a production container with uWSGI which we'll use to actually run the service. A second job will run to install Selenium/Chromium/tox/etc and run those tests separately. Unfortunately this has to be separate, because a) we really don't want a full browser and graphics stack in our live production container, and b) tox installs all its dependencies into a separate venv that it creates. This means that we want to run the tests twice - once on the prod container, and again via tox, because tox is only testing locally, not against what's actually installed.