This change adds a docker compose configuration that's used with
the `elasticsearch.test.fixtures` plugin to start up the image
and check that the TCP ports are up.
We can build on this to add other checks for culster health,
run REST tests, etc.
We can add multiple containers and configurations to the compose
file (e.x. test different env vars) and form clusters.
With the release of 11.0.2, the old URLs no longer work. This exposed a
few small bugs in the gradle config. One was that --no-cache was not
present in the docker build command, so it was not failing at
first. Then once only the ext.expansions was changed and the docker
build task was not, it was not executing it.
This commit introduces the building of the Docker images as bonafide
packaging formats alongside our existing archive and packaging
distributions. This build is migrated from a dedicated repository, and
converted to Gradle in the process.
Alpar Torok
Michael Basnight
Jason Tedor