feature: multiple port mapping

[h0lm0]

Hello,

I've been using Bore for a while, and it has simplified a lot of my tasks, thank you for that!

I just thought of a potential new feature: adding the ability to map multiple ports in a single command. I’m not sure about the best approach for this, but one option might be to allow for an input file that maps client and server ports, for example, an .ini file like this:

8080=80
4443=443

or toml file, etc

Here, 8080 and 4443 would be the local ports, and 80 and 443 the remote ports.
Do you think this might be feasible?

Thank you!