Reconfigure how releases.html, whatsnew.html and hugo version release markdown are generated

The website release history/archive has pages that reflect the informaiton found in help/help/html/whatsnew.html (for the current version) and in help/help/html/releases.html

To consistently generate the release archive page for a new version, configure build.gradle to take markdown from two files
help/markdown/whatsnew/whatsnew-VERSION.md
help/markdown/releases/release-VERSION.md
to create the hugo markdown page and whatsnew.html, and to use all of the help/markdown/releases/release-*.md files to re-generate releases.html