Allow user to specify their own port for SSH

[v1shwa]

While it is very uncommon to have ssh on different port, I believe it would be a great addition for

• Testing locally where one can spin-up containers which are usually bound to various ports.
• For those who actually have ssh on a different port.

Let me know if this makes sense to you. I'd be more than happy to submit a PR for this.

[pch]

Yes, it makes sense. I usually do it via ~/.ssh/config but it would be a nice addition to welder. I'd be happy to see a PR for it 👍