Multi-cell adoption support

[bogdando]

Adapt vars for multi-cell layout.
Remove no longer used edpm_computes.

Assume a single default cell exists only (which becomes cell1
after adoption).

Change data formats to become compliant with multi-cell topology.

Depends-On: openstack-k8s-operators/data-plane-adoption#746
Closes: openstack-k8s-operators/data-plane-adoption#184
Jira: #OSPRH-6548

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[softwarefactory-project-zuul]

This change depends on a change that failed to merge.

Change openstack-k8s-operators/data-plane-adoption#746 is needed.

[softwarefactory-project-zuul]

This change depends on a change that failed to merge.

Change openstack-k8s-operators/data-plane-adoption#746 is needed.