Support client-specific tls-crypt keys

[randshell]

OpenVPN 2.5 added support for client-specific tls-crypt keys (--tls-crypt-v2) which in case of the compromise of a client only that client's pre-shared key would be affected. What we do currently is using the same shared key for every user.

Documentation at https://github.com/OpenVPN/openvpn/blob/master/doc/tls-crypt-v2.txt

[TinCanTech]

This is exactly what Easy-TLS is for. (Sorry for the spam)

[alpe12]

@angristan Please add this.
Easy-TLS isn't easy enough for me. :(