Improved docs for the two modules, operator and restic

docs/modules/ROOT/pages/explanations/architecture.adoc

@@ -2,8 +2,8 @@
 
 K8up consists of two parts:
 
-* Kubernetes Operator: https://github.com/vshn/k8up[K8up]
-* Restic wrapper: https://github.com/vshn/k8up/[wrestic]
+* Kubernetes Operator: https://github.com/vshn/k8up/tree/master/operator[K8up]
+* Restic wrapper: https://github.com/vshn/k8up/tree/master/restic[wrestic]
 
 == High Level Description
 

operator/README.md

@@ -0,0 +1,11 @@
+# Operator Support Code
+
+This Go module contains almost all of the code that supports the operator part K8up.
+
+The CLI entrypoint is in [`cmd/operator`](../cmd/operator).
+
+The rest of the operator's code follows the layout that [the _Operator SDK_](https://sdk.operatorframework.io/docs/building-operators/golang/) expects:
+
+- [`/api`](../api/v1alpha1) contains the custom resource definitions (CRDs)
+- [`/config`](../config) contains configuration and sample files
+- [`/controllers`](../controllers) contains the controllers which act on the events of the CRDs (and other events) through reconciliation loops

restic/README.md

@@ -0,0 +1,5 @@
+# Restic Backup Implementation
+
+This Go module contains the bulk of the implementation to support Restic backups.
+
+The CLI entrypoint is in [`cmd/restic`](../cmd/restic).