Dualstack support for Loadbalancer Services

[flawedmatrix]

As a preliminary step towards dualstack support, I've made some changes to allow handling the case where the field metadata.annotations["kube-vip.io/loadbalancerIPs"] has multiple IPs.

Right now, there are some cases where I couldn't quite figure out the best UX for multiple loadbalancer IPs for a single service, so for now I'm only supporting dualstack LoadBalancer services in the EnableARP configuration of kube-vip and leaving cases like DHCP, EnableBGP, and uPnP as supporting only one LoadBalancer IP per service. Also egress only supports the first IP in the list of loadbalancer IPs.

I think I'd like to do some more cleanup for this PR, but I've added a test for a dualstack LoadBalancer service and it passes now:

time="2023-12-16T04:02:44Z" level=info msg="🧪 ---> testing dualstack loadbalancer service <---"
time="2023-12-16T04:02:44Z" level=info msg="📝 created deployment [kube-vip-deploy]"
time="2023-12-16T04:02:44Z" level=info msg="🌍 creating service [kube-vip-service]"
time="2023-12-16T04:02:44Z" level=info msg="🔎 found load balancer addresses [[172.18.255.250 fc00:f853:ccd:e793:ffff:ffff:ffff:fffa]] on node [services-worker2]"
time="2023-12-16T04:02:44Z" level=info msg="🕷️  testing HTTP request against [172.18.255.250]"
time="2023-12-16T04:02:47Z" level=info msg="🕸️  successfully retrieved web data in [2s]"
time="2023-12-16T04:02:47Z" level=info msg="🕷️  testing HTTP request against [fc00:f853:ccd:e793:ffff:ffff:ffff:fffa]"
time="2023-12-16T04:02:49Z" level=info msg="🕸️  successfully retrieved web data in [1s]"
time="2023-12-16T04:02:49Z" level=info msg="🧹 deleting Service [kube-vip-service], deployment [kube-vip-deploy]"

[thebsdbox]

Wow, this is incredible! (Thank you ever so much for this piece of work)

[thebsdbox]

Looks good to me, is there anything additional that is needed?

[flawedmatrix]

Thanks for the comment! I wanted to do a final glance-over to make sure I didn't miss anything, but I think this PR is good to go now.