SOLR-15949: Docker, use Java 17

[dsmiley]

azul/zulu-openjdk-alpine:17-jre-headless

Also switched OS from Debian to Alpine. WIP

https://issues.apache.org/jira/browseSOLR-15949

It wasn't easy to find a Java 17 JRE in Docker hub but I ultimately did with Azul. I trust them.

In my attempt to do this, I wound up choosing Alpine, which is another, perhaps bigger change. I'd be happy to move this off to another issue; I really should but I'm pushing this now to show what I have since I put time into it. I think most edits and possible further TODO in this PR are due to Alpine.

• I added su-exec instead of gosu which I found easier to install, and I hear it's smaller. I removed to gosu test; honestly I'm not sure where it's used -- if nowhere then maybe we don't need a test.
• init-var-solr was using cp -a ... but I saw warnings because the owner couldn't be preserved, which makes sense. This could be done independently of this PR; it may not be related but it was a warning I saw.
• I tested gradlew testDocker and it passes.
• I suspect the official image building might not work because I didn't find all of the unix add-ons when converting to apk. I didn't try it yet; this is a TODO.

[dsmiley]

I saw this JIRA issue about lsof https://issues.apache.org/jira/browse/SOLR-13089 that was closed because we moved away from Alpine once but may be relevant again.

[dsmiley]

FYI https://hub.docker.com/r/azul/zulu-openjdk-alpine/tags
JRE vs JDK saves almost 80MB which is a ton. Interestingly the "-headless" seems to change nothing for the image sizes. Note that the numbers there are compressed numbers. When it gets to your machine, these expand significantly.

[HoustonPutman]

As for the change from debian to alpine, I don't think we can use that image as our default base image: https://github.com/docker-library/official-images#repeatability

Official images can't be built on top of non-official images.

[janhoy]

Propose we use eclipse-temurin:17-jre which is an official jre image, slimmer than openjdk:17-slim.

[janhoy]

Tested SOLR_DOCKER_BASE_IMAGE=eclipse-temurin:17-jre ./gradlew dockerBuild and started the resulting image. Worked great. Just add CHANGES and possibly major-changes entries and we shuold be good.

[HoustonPutman]

Looks good to me too.