This change removes files that are no longer needed with the gradle
build. The license checker was already rewritten in groovy. The plugin
descriptor template exists in buildSrc resources. log4j properties was
moved to the test framework. site_en.xml seems to be a legacy file,
there are no references to it anywhere in the maven build that I could
find. The update lucene script was just a helper for running the license
check in update mode, but that can be done with gradle using the
updateShas command. Finally, there was a leftover build.gradle from when
I attempted to make dev-tools a project of its own.
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