docs: extend docs

docs/getting_started.md

@@ -1,5 +1,11 @@
 # Getting Started
 
+## Dependencies
+
+The operator has the following dependencies:
+
+- [cert-manager](https://cert-manager.io/) (to issue webhook certificates)
+
 ## Deploying the operator
 
 The easiest way to deploy the operator is to fetch the manifest from the [releases](https://code.icb4dc0.de/prskr/supabase-operator/releases) and apply it like this:
@@ -12,3 +18,12 @@ The manifest is rendered as part of the release workflow and based on [kustomize
 If you want to customize the deployment, you can start from the [release/default](https://code.icb4dc0.de/prskr/supabase-operator/src/branch/main/config/release/default) layer and build your own manifest.
 
 ## Deploying a basic Supabase instance
+
+As described in the [overview](./components/overview.md) the custom resources are 'grouping' the Supabase services into 'modules'.
+A common basic instance requires:
+
+- a [`Core`](./components/core.md) instance (PostgREST, Auth & DB migrations)
+- an [`APIGateway`](./components/apigateway.md) instance (gateway to handle JWT auth and routing)
+
+it is perfectly possible to deploy for instance only an `APIGateway` and a `Storage` instance as well if you don't need the API or you can also manage your own API gateway if you prefer it that way.
+The operator setup tries to be as 'unopinionated' as possible.