Resolve "Document product integration for creating flux, secrets, namespaces, and values resources"

See #842 (closed) and parent epic for details

Closes #842 (closed)

docs/developer/package-integration-database.md

+# Big Bang Package: Database Integration
+
+If the package you are integrating connects to a database or cache server, you will need to follow the instructions below to integrate this feature into Big Bang
+
+## Prerequisites
+
+TBD
+
+## Integration
+
+## Validation