Documentation fix for significant_terms heading levels
[TEST] Use client node such that we always have to do a round-trip to do a fetch.
Move systemd files from /etc to /usr/lib

As documented in systemd's manual pages tmpfiles.d(5) and systemd.unit(5),
a package should install its default configuration in /usr/lib, which can
be overriden by system administrators in /etc.

New locations in the rpm:
/usr/lib/systemd/system/elasticsearch.service
/usr/lib/tmpfiles.d/elasticsearch.conf
cleanup formatting in significant aggs package
[TEST] Print tests.jvms and tests.client.ratio if set

We need to print options that can modify stream of events we need
to print it otherwise a seed might not reproduce the failure in
the tests.