Supervisor storage garbage collection controller enabled in production

- Also add more log statements to the controller
- Also have the controller apply a rate limit to itself, to avoid
  having a very chatty controller that runs way more often than is
  needed.
- Also add an integration test for the controller's behavior.

Signed-off-by: Margo Crawford <margaretc@vmware.com>

cmd/pinniped-supervisor/main.go

@@ -29,6 +29,7 @@ import (
 	"go.pinniped.dev/internal/config/supervisor"
 	"go.pinniped.dev/internal/controller/supervisorconfig"
 	"go.pinniped.dev/internal/controller/supervisorconfig/upstreamwatcher"
+	"go.pinniped.dev/internal/controller/supervisorstorage"
 	"go.pinniped.dev/internal/controllerlib"
 	"go.pinniped.dev/internal/downward"
 	"go.pinniped.dev/internal/oidc/jwks"
@@ -84,6 +85,15 @@ func startControllers(
 	// Create controller manager.
 	controllerManager := controllerlib.
 		NewManager().
+		WithController(
+			supervisorstorage.GarbageCollectorController(
+				clock.RealClock{},
+				kubeClient,
+				kubeInformers.Core().V1().Secrets(),
+				controllerlib.WithInformer,
+			),
+			singletonWorker,
+		).
 		WithController(
 			supervisorconfig.NewOIDCProviderWatcherController(
 				issuerManager,