add support for auto detecting cluster domain

[meridional]

Previously, the cluster domain is hardcoded to cluster.local.

This PR adds support for auto detecting the domain by running a DNS query.

This addresses the issue #893.

Checklist

• [x] I have added these changes to the changelog (or it's not applicable).

[Lamercho]

when we can expect new release with last merges ?

[edgarlanting]

@chrisseto Can we please get this one retested/rebased please? Would be pretty nice to get this implemented.