Rewrote sync to avoid false modifications

Still working on Dns which has can have multiple recs for each
key (e.g., TXT, A, NS)

Also get_or_create is deprecated so use separate calls.
Merge DNS records for each name to avoid diffs

We have to aggregate all the records for a given name (e.g., TXT, A,
SOA) else we get all the records back in random order and we comare a
TXT record with a SOA record and register false positives.

Does the version comparison work later with the list of resource
records, or does the unstable order of that list cause false
comparisons?

Do we really need class-based comparison methods, a generic one then
class-specific overrides for things like DNS?
Sort SecurityGroup CIDR blocks and UserGroups

So that comparisons with old versions are stable.