Originally written by @AlexanderSaydakov in druid-io/druid-io.github.io#448.
I also added redirects and updated links to point to the new
datasketches-extension.html landing page for the extension, rather than to
the old page about theta sketches.
* Move caffeine out of extension.
* Remove `JsonTypeName` from the class itself
* Fix bad docs
* Fix distribution pom
* Fix unused import
* Make caffeine default
* Address code comments
* Add more description around the jre version in the readme
* Add suggested comments
- Make redirects for old links based on _redirects.json
- Replace #{DRUIDVERSION} tokens in docs with current version
- Allow origins named something other than "origin"
- Can use either s3cmd or awscli, depending on availability
Gian Merlino
Charles Allen