fix: make port 0 bind to any available port

[davidmurdoch]

Specifying a port of 0 is a way to tell a server that you want the Operating System to let you bind to any open port. Ganache claimed to support binding to port 0, but would rudely yell at you if you tried: Port should be >= 0 and < 65536. Received 0 🤦! This PR rights our wrongs.

Using port 0 is useful when you don't care which port you bind to, you just want an open port.

You can use port 0 in a few ways:

On the cli:

$ ganache --port 0
…
RPC Listening on 127.0.0.1:35006

In detach mode:

$$\color{#8b949e}\textsf{note: port 0 binding in detach mode doesn't yet provide a scripting friendly way of returning the port}$$

$ ganache --detach --port 0
frozen_caramel_doughnut

$ ganache instances list
┌───────┬─────────────────────────┬──────────┬─────────┬─────────────────┬────────┐
│   PID │ Name                    │ Flavor   │ Version │ Host            │ Uptime │
├───────┼─────────────────────────┼──────────┼─────────┼─────────────────┼────────┤
│ 58078 │ frozen_caramel_doughnut │ ethereum │ 7.7.3   │ 127.0.0.1:35006 │    14s │
└───────┴─────────────────────────┴──────────┴─────────┴─────────────────┴────────┘

and programmatically:

import ganache from "ganache";

const server = ganache.server();
await server.listen(0);
console.log("Listening on port: ", server.address().port);

Fixes #2643 and #3805

[MicaiahReid]

I think this is a fix because we claimed to support binding to port 0.