* Remove PyOpenSSL based wrapper classes
* Remove unused API calls
* Add certificate renewal via X-Renewal-Signature header
* Remove (extended) key usage handling
* Clean up OpenVPN and nginx server setup code
* Use UDP port 51900 for OpenVPN by default
* Add basic auth fallback for iOS in addition to Android
* Reduce complexity
* Replace PyOpenSSL with cryptography.io
* Rename constants to const
* Drop support for uwsgi
* Use systemd to launch certidude server
* Signer automatically spawned as part of server
* Update requirements.txt
* Clean up certidude client configuration handling
* Add automatic enroll with Kerberos machine cerdentials
* Add abstraction for user objects
* Mail authority admins about pending, revoked and signed certificates
* Add NetworkManager's OpenVPN plugin support
* Improve CRL support
* Refactor CSRF protection
* Update documentation