We generate javadoc from arvados-sdk-java, this means the hook that updates doc.arvados.org needs be able to run javadoc (requires gradle and java sdk to be installed)

14670-new-java-sdk-docs arvados/sdk/java-v2 * Need to rename the package, this is probably just a matter of editing "settings.gradle". The legacy package was called "arvados-sdk-1.0" and the new package was called "arvados-java-2.0" so I think we want to rename it to something like "arvados-java-sdk-1.x" or "arvados-java-client-1.x" so it doesn't conflict with past packages and we can reset the version series to match our release schedule. * Need to generate package versions that are in sync with our other packages. This should use the same approach (latest git tag + timestamp of latest commit to the arvados/sdk/java-v2 directory) we use to generate the version for the Python client. * Need to publish the artifact is a maven-compatible repo (so it can be pulled by maven / gradle / etc build systems conveniently). Either we set up our own on arvados.org, or push to something like maven central. * Update the documentation to explain how to fetch the package from the artifact repo.