[DB Compatibility] Add DB compatibility progress chart to Fidesops docs

[seanpreston]

Our current DB compatibility roadmap is mapped out here: https://ethyca.atlassian.net/wiki/spaces/OSS/pages/2162393244/fidesops+Self-Hosted+DSR+Automation+Requirements#Database-%26-Schema-Compatibility-Requirements

We should add the current version of this to its own (or a roadmap?) page on our docsite, and keep it up to date in the future.