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

##### ISSUE TYPE

* Feature Idea

##### COMPONENT NAME

~~~
UI,API,Guest Network

~~~

##### CLOUDSTACK VERSION

~~~
N/A
~~~

##### 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

~~~
N/A
~~~

##### EXPECTED RESULTS

~~~

~~~

##### ACTUAL RESULTS

~~~
N/A
~~~

Das Issue identifiziert UI, API und Guest Network als betroffene Komponenten, nennt jedoch keine Dateien oder Tests. Beginne damit, die Workflows für guest-network-Portweiterleitung und Load-Balancer nachzuverfolgen. Als abgeschlossen gilt die Aufgabe, wenn Benutzer IP-Entitäten unter einem Guest Network erstellen und sie in Port-Forward- und Load-Balancer-Zuordnungen verwenden können.

Vom Indexierungsmodell aus dem Issue-Text verfasst.