Add SoftEther VPN Server/Client

[pcislocked]

Please check the project here: https://github.com/SoftEtherVPN/SoftEtherVPN

It's a FOSS VPN server/client suite that has its own protocol that can run over TCP, UDP or ICMP, or accept connections from other VPN protocols such as WireGuard, OpenVPN or L2TP. It has many more features that I can't use because I don't understand how they work fully, but what I understand at the end is it is a very powerful VPN server and it should definitely be on the list. It uses apache 2.0 license.

[Technetium1]

Already added in 2014!