Extend ignored_guest_ips to support CIDR networks

[isometry]

• Correctly parse CIDR networks included in the ignored_guest_ips list, allowing entire arbitrary IP ranges to be ignored.
• Compare guest IP addresses to ignored_guest_ips using net.IP.Equal() rather than raw string comparison, enhancing support for variations in IPv6 representation.

[isometry]

Patch updated following testing. Is there anything else required from me before this can be merged?

We need the functionality in order to prevent the provider from binding to the temporary DHCP IP temporarily detected even when we assign a fixed IP via Guest Customization, for example if the attached subnet hands out dynamic addresses in 10.0.0.128/25 but we need to assign a static IP outside that range, foo.default_ip_address will be a DHCP address which is no longer valid after VMware Guest Customization has completed:

resource "vsphere_virtual_machine" "foo" {
  …
  ignored_guest_ips = ["10.0.0.128/25"]
  clone {
    …
    customize {
      …
      network_interface {
        ipv4_address = 10.0.0.10
        ipv4_netmask = 24
      }
    }
  }
}

[koikonom]

Hi @isometry,

First of all, thanks for taking the time to submit the PR. The feature you introduce looks useful. I have a comment around the validation of the CIDR strings, but other than that it looks OK.

[isometry]

@koikonom : I'm not sure why this PR is still marked "Changes Requested", but I implemented the changes you suggested two weeks ago. Any chance of getting this merged before v1.14.0?

[koikonom]

Hi @isometry, I am sorry for the delay. We have been having some issues with our acceptance tests lately so I've spent all my time getting these in order first. Once we are confident that things are back in working order I will merge this PR (before v1.14.0).

[koikonom]

LGTM