Python 2 has been EoL-ed and we no longer support it.

Add the supported LTS Django versions. As of writing Django 3.1 is
EoL-ed in a week so it doesn't seem worth keeping it in the matrix.

Remove Python 3.5 as it is EoL-ed and add in Python 3.8 and 3.9.

Bring in the Auto-DevOps template from GitLab. We do our own matrix
testing but this brings in the various security, lecence and dependency
scanning tools from Auto-DevOps.

In order to make use of these scanning tools we build a small container
but this is not intended to run the application, just to contain the
source so that the various scanners can scan it. That being said we do
"pip install" within the container so that a basic "pip install" test
must pass before we start all the rest of the test jobs.

Closes #7

Add a basic CI configuration which matrix tests against supported
Python and Django versions along with running flake8 and code-coverage.
Coverage information is extracted from the coverage job run.

Closes #6