The credentials now get injected via environment variables, so that
external services can pull those.
As soon as the specified environment variables are set, the tests are run. No need to check for the @Network annotation
This also introduces new secret store settings for the secure settings in order to be sure to not leak them in the configuration files, that get dumped.
Relates elastic/x-pack-elasticsearch#3800
Original commit: elastic/x-pack-elasticsearch@a2cfb9cb86
Alexander Reelsen
Deb Adair
lcawley