Upgrade base image to Ubuntu 23.04 and work around changes to the way…

… easyrsa imports variables.

Fix easy-rsa issues and update the README.

Updated README

Ubuntu (#51)

* Debian

* Make Ubuntu the base.  Update TLS ciphers.  Ensure the openvpn log file exists for fail2ban.

* Fix default cipher string and log date format.  Add the ability to override the OpenVPN port.

* Updated README formatting, add a random file for easyrsa, allow specifying the OpenVPN port.

Update README.md

Allow manual configuration (#35)

* Add env variable to append extra options to server config

* Add option to configure server by hand

Merge pull request #31 from wheelybird/cacert_fix

Cacert fix

Merge pull request #26 from wheelybird/active_directory

Fix variable name error and also set the login attribute required by AD

Fix markup errors