Make runserver handle HTTPS requests.

[Éloi Rivard]

Hi. The builtin manage.py check --deploy encourages to enable all the available securities, including SECURE_SSL_REDIRECT that actually redirect any non HTTP request to a HTTPS request. However manage.py runserver does not allow HTTPS requests. It is too bad that we cannot test all the available options in development before we deploy an app.

The existing ​django-sslserver solves the issue, quite simply. But on the other hand, manage.py runsslserver does not allow simple HTTP request.

I think this would be a good idea to enhance the current runsslserver with what we can find in django-sslserver, so in the end it can handle both HTTP and HTTPS requests.

I am OK to make a merge request if you are interested.

[Tim Graham]

This was previously proposed on ​django-developers and declined in favor of other options.