Previous way skipped all multicast queries when unicast DNS contains
local. SOA record. Change that behaviour and always request multicast
name. But if local SOA is present, then make missing multicast optional
and continue to DNS plugin. That would make names ending with .local to
take longer resolve on unicast DNS, but should still deliver the answer.

Use new enum to specify forced present or missing .local SOA record. Use
from production code auto value, but use forced values from unit test.
Add few different results to unit test.