Fix deprecation warnings and README samples

[prologic]

Managed to fix the deprecation warnings I was seeing with:

  disk {
    id = 0
    type = "scsi"
    storage = "zfs"
    size = 8
  }

  cores   = 1
  sockets = 1
  memory  = 2048

  network {
    id = 0
    model = "virtio"
    bridge = "vmbr0"
  }

The README should be updated to reflect latest changes in mazter.

[hbokh]

This line is wrong and will result in "400 Parameter verification failed":

ipconfig0 = "ip=10.0.2.99, gw=10.0.2.2"

It is missing a CIDR like <IPv4Format/CIDR>

so should read something like:

ipconfig0 = "gw=10.0.2.2,ip=10.0.2.99/24"