Support topology extend with multiple host-address

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Currently a user can add multiple --host-address in virsh plugin to spawn nodes on different kvm host.
Looking at the code, it seems '--topology-extend' is only expected to work on single host-address, based on the _run_condition value derived in "Pre run configuration" .
I was hoping that if I run virsh with X host-address and at a later time run it again with X+Y number of hosts along with extend option, then new value of each node count is distributed across the Y nodes.
The current behavior is that when a virsh command is run again with new host-address and topology extend option, the new vms are spawn in the older host.

The functionality we are looking for is to spawn different number of compute/overcloud nodes on different host as these hosts may have dissimilar resources like memory , cpu etc.