vlans: rework vlan_create_many_vlans
Do not add it's own dns record for each VLAN and wait up to 120s before asking for number of VLANs (to give NM some rest).
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The migration is almost done, at least the rest should happen in the background. There are still a few technical difference between the old cluster and the new ones, and they are summarized in this issue. Please pay attention to the TL:DR at the end of the comment.
Do not add it's own dns record for each VLAN and wait up to 120s before asking for number of VLANs (to give NM some rest).