Support for IP address allocation mechanisms

Most straightforward: BoxOptions supports static IPs (example assumes API)
If the API supports it, you can pass it like this:

```
box_opts = boxlite.BoxOptions( image="alpine:latest", ip="192.168.50.10", netmask="255.255.255.0", gateway="192.168.50.1" )
box = runtime.create(box_opts)
```

Pros: simple and straightforward, with the runtime taking care of getting the network interface configured.

Start by reviewing the BoxOptions and runtime.create API entry points named in the issue, and determine how IP, netmask, and gateway allocation should be represented. Done means a defined allocation mechanism supports the requested static-IP example and its behavior is covered by the project's relevant validation or runtime checks.

Written by the indexing model from the issue text.