Lease an IP for a group of VMs

[OpenNebulaSupport]

Description
One needs to have a possibility to assign floating/virtual IP address to a group of VMs.

Use case
Possible use cases can be the following but not limited to:

1. HAproxy cluster deployed as a service.
2. Database cluster consisting of several VMs sharing a set of IP addresses.
3. Several services on linux VMs that needs to be configured in HA with VRRP.
4. Virtual firewall cluster appliance with multiple addresses.
   and so on.

Interface Changes
should become more clear during implementation phase.

Additional context
One of the possible implementation could be based on the use of flow. The same way one can create a network from a flow, one can do the same with an IP and use that in the VM templates. So the user will need to create a flow, with all VMs and allocate an IP in the flow template.

Progress Status

• Code committed
• Testing - QA
• Documentation (Release notes - resolved issues, compatibility, known issues)