* Upgrade Django to 3.0 and other dependencies to recent versions
* Fix otp version contsraint
* Remove six dependency
* Resolve some warnings
* Fix failing tests
* Update django-countries
* Resolve all RemovedInDjango31Warnings in test suite
* Run isort
* Fix import
* Update PostgreSQL version on travis
* Remove check password for event deletion, instead require recent login.
* Reauthenticate for backends using authentication_url.
* Require recent login for data shredder and prompt slug instead of password.
* Fix tests for recent login required on event delete and data shred.
* Pull request remarks for recent login required for event delete and data shred.
* Remove unused imported check_password.
Here is my attempt to prevent user enumeration.
I've made the following changes:
**Application:**
- replaces success and failure messages in the form with two (with/without redis) information messages
- adds logging for attempted password resets of unknown users
- adds logging for failing emails
**Tests:**
- test_unknown asserts a redirect instead of a ok
- adds test_email_reset_twice_redis to assert the correct logging of a twice reset email
- adds a FakeRedis class similiar to the one implemented in test_metrics.py. I could refactor them into the testutils folder if prefered.
Please excuse the commit mess. I am currently fighting with my tooling.
