Add Networking metadata to Libvirt XML

### The required feature described as a wish

Libvirt allows for adding Metadata to the XML of a Domain: https://libvirt.org/formatdomain.html#general-metadata

We can use this Metadata to add additional information of the Instance so that it can be used by Libvirt hooks: https://libvirt.org/hooks.html#etc-libvirt-hooks-qemu

My proposal is to add basic IP address information to the XML:

```

```

Hooks can prepare additional firewalling or routing on the host while it is booted, this is up to the admin to decide.

Start by tracing how CloudStack produces Libvirt domain XML and review the Libvirt domain metadata and hook documentation linked in the issue. The work is complete when the generated XML includes the requested network address metadata, including address, prefix, family, bridge, and VLAN values for applicable IPv4 and IPv6 networks.

Written by the indexing model from the issue text.