Versioned documentation

[anders-swanson]

The README.md file currently contains features for the in-development release, which can be confusing. The documentation must be revamped into a versioned website, so users can easily find the information for their specific release.

[anders-swanson]

Docs: https://oracle.github.io/oracle-db-appdev-monitoring/

Starting with 2.0.3, documentation will be versioned into release tags and "next", representing the in-development changes.