Ozone: Documentation: Add version specific documentation site to KSM

In HDFS-12661, elek has supported the ability to have version specific documentation for KSM. In other words, with HDFS-12661, it checks if Documentation is checked in and if so it will appear as "Documentation" Link on the KMS UI. The makes it easy to have accurate and version specific documentation for ozone.

This JIRA proposes to add the first draft of the documentation that can be accessed via KSM UI. This is independent of the standard Ozone documentation that we add to the HDFS documentation.