NMS-6825 wait for full DNS server startup

Fix a potential race condition by waiting for DNS threads to fully
come up before start() returns.
NMS-6824 fixes for testGetAvailability

I modified the remote poller test to use a single set
of start/end times rather than re-instantiating Date
or calling currentTimeMillis multiple times, to create
less jitter while doing time-related math.
Added Eventd features to OpenNMS feature repository.
NMS-6828 giving up on VacuumdTest

It would take WAY too much work to rearchitect Vacuumd to be
properly testable.  We've gone so far into code debt that after
a vote, we've decided to declare code bankruptcy.
Merge remote-tracking branch 'origin/1.12'

Conflicts:
	opennms-alarms/daemon/src/test/java/org/opennms/netmgt/vacuumd/VacuumdTest.java
Moved some util classes into core/lib in an effort to get Eventd to load
in Karaf.
Added more dependencies to the features.xml. Reversed the daoContext and
the daemonContext in the context inheritance hierarchy (because daemon doesn't
require dao). Added Spring DM context for features/events/daemon to try and
link it up with OSGi services.
Merge commit 'ccea887f6a5ff0488040d89e7dfc9e576e6f5cca' into feature-refactor-eventd-trapd-merge1
Merge branch 'feature-refactor-eventd-trapd-merge1' into feature-refactor-eventd-trapd