docs: initial CI setup

docs/components/overview.md

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+# Overview
+
+## Architecture
+
+The following diagram explains the overall architecture of Supabase as it is deployed from this operator:
+
+```kroki-excalidraw
+@from_file:./images/overview.excalidraw
+```
+
+The dashed parts on the left are not managed by this operator but illustrate how traffic can be routed to the Supabase instance.
+
+## Core
+
+The `Core` custom resource (CR) is the basic resource that - if not in an 'edge case' (pun intended) - configures all basic aspects of a Supabase instance:
+
+- PostgREST API
+- Supabase Auth
+- initial database migrations