[Feature]: Add port configuration option

[daveskybet]

What problem does this feature solve?

When working inside docker containers, the current random approach for assigning a port number makes things a little tricky when opening port numbers inside a docker compose file (for example). Allowing users to provide a port number of their choosing would alleviate this problem.

What does the proposed API look like?

There are a few ways this could be done, adding a port option in the options config, or an env var are two that spring to mind.

[yifancong]

OK, I will put this issue in the TODO List, please pay attention to it.