u2o support specify u2o ip on release-1.11

[changluyi]

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

What type of this PR

Examples of user facing changes:

• Features
• Bug fixes
• Docs
• Tests

Which issue(s) this PR fixes:

Fixes #(issue-number)

WHAT

🤖 Generated by Copilot at 7e2de89

This pull request adds a new feature to allow user-specified or dynamic IP addresses for the underlay to overlay interconnection in subnets. It modifies the SubnetSpec and SubnetStatus schemas, the subnet controller logic, and the subnet validation function. It also updates the kube-ovn-crd.yaml and crd.yaml files to reflect the schema changes.

🤖 Generated by Copilot at 7e2de89

Oh we are the coders of the kube-ovn
We make the subnets interconnect
We heave and we ho and we validate
The u2oInterconnectionIP we set

HOW

🤖 Generated by Copilot at 7e2de89

• Add a new field U2OInterconnectionIP to the SubnetSpec struct to specify a static IP address for the underlay to overlay interconnection (link)
• Add a new field u2oInterconnectionIP to the SubnetStatus schema in the kube-ovn-crd.yaml and crd.yaml files to store the IP address of the logical router port that connects the overlay subnet to the underlay network (link, link)
• Validate the U2OInterconnectionIP field in the ValidateSubnet function and ensure that it is within the subnet CIDR and not conflicting with the logicalGateway field (link)
• Enqueue the subnet key for processing when the U2OInterconnectionIP field changes in the enqueueUpdateSubnet function (link)
• Clear the U2OInterconnectionIP field if the U2OInterconnection field is false and set the changed flag to true in the formatSubnet function (link)
• Allocate or release the IP address for the underlay to overlay interconnection and update the subnet status accordingly in the reconcileU2OInterconnectionIP function, handling the cases where the U2OInterconnectionIP field is specified or changed by the user (link)