Test clusters currently has its own set of logic for dealing with
finding different versions of Elasticsearch, downloading them, and
extracting them. This commit converts testclusters to use the
DistributionDownloadPlugin.
Move `x-pack/qa/smoke-test-graph-with-security` to
`x-pack/plugin/graph/qa/security` which should make it easier to run all
of the tests with a single command. It also lines up the directories
more closely with newer projects like cross cluster replication.
Ryan Ernst
Alpar Torok
Mark Vieira
Nik Everett