The doc links in scylla-sstable help output are static, so they always
point to the documentation of the latest stable release, not to the
documentation of the release the tool binary is from. On top of that,
the links point to old open-source documentation, which is now EOL.
Fix both problems: point link at the new source-available documentation
pages and make them version aware.
(cherry picked from commit fe73c90df9)