Converts over from elasticsearch to opensearch to support
the upcoming migration. The repo should similarly be renamed
in gitlab to reflect that it is now an opensearch image.

Light changes to the build were required.
* renamed elasticsearch to opensearch everywhere
* the opensearch image is rpm based, was easiest to bring in an
 additional unpack phase to building that uses debian to unpack
 the production .deb
* Added functionality to more easily test the built container
  with a custom plugins .deb
* Disables the opensearch security plugin. This matches how
  opensearch will initially be deployed in prod.

Related patch builds the opensearch .deb. That .deb is missing
a variety of plugins and does not pass test-opensearch.sh.

Bug: T372769
Related: I50a8f0ea5085b9f8b0c3627932f198aef0ed00ea