split ippoolname and old ippool

[bobz965]

• Make sure you have followed Kube-OVN Code Style.

What type of this PR

Examples of user facing changes:

• Bug fixes

Which issue(s) this PR fixes:

Fixes #3050

WHAT

🤖 Generated by Copilot at 1674ca4

Refactored the code to use a new annotation key util.IpPoolNameAnnotation for IP pool assignment and update for namespaces and pods. Added support for IP pools in dual stack subnets. Updated the test cases and constants accordingly.

🤖 Generated by Copilot at 1674ca4

Oh we're the crew of the kube-ovn
And we work on the code all day
We refactor the annotation key
To make the IP pools work our way

HOW

🤖 Generated by Copilot at 1674ca4

• Refactor annotation keys for IP pools to use util.IpPoolNameAnnotation instead of util.IpPoolAnnotation for consistency and clarity (link, link, link, link, link, link, link)
• Add support for specifying IP pools for pods in dual stack subnets by getting the IP pool name annotation from the pod if it exists (link, link)
• Modify acquireAddress function in pkg/controller/pod.go to handle the case where the pod or the namespace has a single IP pool name annotation instead of a list of IP addresses and allocate an IP address from the IP pool by name using the GetRandomAddress method of the IPAM module (link)

[bobz965]

it has another pr, so closed