Add Support IPAM object to Allow Load Balancer or Port-forward map to floating IP Address

##### ISSUE TYPE

* Feature Idea

##### COMPONENT NAME

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UI,API,Guest Network

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##### CLOUDSTACK VERSION

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##### CONFIGURATION

##### OS / ENVIRONMENT

##### SUMMARY

When a Guest Network was created, the port forward and load balancer features only allow to be configure with pre-existing VM in same Guest Network. Sometime user will deploy self managed virtual ip address to support their application such as keepalived, MetalLB..etc. Today, the user will add a secondary NIC to the one of VM instance and then use the assigned NIC ip address to treat the virtual ip setup. Most of the time, it is unavoidable to use this appoarch when LB pool health check limit to L4 port checking.

I'm wondering if ACS can implement IPAM management abstract under guest network to allow user create IP entities which will able to include into port forwarding or Load balancer member.

##### STEPS TO REPRODUCE

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##### EXPECTED RESULTS

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##### ACTUAL RESULTS

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N/A
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该 issue 指出 UI、API 和 Guest Network 是受影响的组件，但没有列出文件或测试。首先跟踪 guest-network 端口转发和负载均衡器工作流。完成标准是用户可以在 Guest Network 下创建 IP 实体，并在端口转发和负载均衡器映射中使用它们。

由索引模型根据 Issue 内容生成。