Add server IP and port expression

[TheDGOfficial]

Is your feature request related to a problem? Please describe.
We can't get the server IP and port, that can be used in for example licensed/paid scripts.

Describe the solution you'd like
We already make a request to the amazon's whatismyip domain at server startup in the static block, on the main Skript class. For my knowledge and research, the external public IP can't be gotten without making a request to a remote service with plain Java.

But for IP, Bukkit has a method and we also already read the server.properties file in the main Skript class, on the JavaPlugin#onLoad method we override to make work arounds.

Describe alternatives you've considered
N/A

Additional information
N/A