docs: break out the configuration complete examples into the main config overview (#546)

website/content/docs/installing/postgres.mdx

@@ -0,0 +1,19 @@
+---
+layout: docs
+page_title: Postgres Installation 
+sidebar_title: Postgres Install
+description: |-
+  Postgres configuration for Boundary 
+---
+
+# Postgres Configuration
+
+This section covers Postgres-specific installation requirements.
+
+## Version
+
+Boundary prefers Postgres 11x or greater. 
+
+## Network 
+
+In non-HA configurations, Boundary serverss must be able to reach Postgres. If you're running in [high availability](/docs/installing/high-availability), then the controllers, and not workers, need access to the Postgres server infrastructure.