Backport of #60742.
This PR resurrects support for building Docker images based on one of
Red Hat's UBI images. It also adds support for running the existing
Docker tests against the image. The image is named
`elasticsearch-ubi8:<version>`.
I also changed the Docker build file uses enums instead strings in a lot
of places, for added rigour.
Backport of #48849. Update `.editorconfig` to make the Java settings the
default for all files, and then apply a 2-space indent to all `*.gradle`
files. Then reformat all the files.
This commit fixes the names of the UBI-based Docker build contexts to
lift the ubi component of the name into the archive base name, instead
of the classifier.
This commit fixes the name of the UBI-based Docker image build contexts
to include "7" (to set us up for the future where we are likely to have
a ubi8-based image).
Rory Hunter
Jason Tedor