As an Administrator I want Django Recaptcha for Captchas

[elmq0022]

The django recaptcha project was dropped by Praekelt Consulting, but is now continued by torchbox, see https://pypi.org/project/django-recaptcha/.

We moved to django-simple-captcha, but it's ability to reduce spam from bots has been significantly less performant.

I would like to move back to django-recaptcha to reduce the amount of spam email we admins receive via chipy.org.