[2] Update the update-ips script to know about Octavia and to allow anchors/overrides

[aarnq]

Is your feature request related to a problem? Please describe.
It is confusing to get warnings about IPs that should exist in the IP lists managed by the update-ips script, since they may be there for a reason but you will not see it unless you manually check either comments in the file or why the got added.
One such point of confusion is the use of Octavia load balancers, since it will want to remove those IPs for every check that is done.

Describe the solution you'd like
I would like it to be aware of when Octavia is in use so it can prompt to add the private subnet instead of adding specific IPs.

Describe alternatives you've considered
Alternatives would be to perhaps preserve comments to show why certain IPs differ or to ignore values with comments when considering the diff, perhaps both for added visibility.
Third alternative would be to just keep override lists, but then it feels like we need to improve our handling of netpol configs in general because it would be too much to maintain in values templates.

(I'm almost more in favour of the second alternative as it would allow us to anchor additions we know we want to keep.)

Definition of done:
The update-ips script is more friendly to use when you need to override IPs.