Implement group resource (#181)

This change implements a new group resource. 

It also sets the standard for a resource reference will be done through
out the controller. A resource reference can either be done by ID or as
a local named reference to the actual resource. This allows end users to
chose if they want to manage things completely in the cluster or not.

Part of #172

Signed-off-by: Philip Laine <philip.laine@gmail.com>

cmd/main.go

@@ -290,6 +290,14 @@ func main() {
 			setupLog.Error(err, "Failed to create controller", "controller", "SetupKey")
 			os.Exit(1)
 		}
+		if err := (&controller.GroupReconciler{
+			Client:  mgr.GetClient(),
+			Netbird: netbird,
+		}).SetupWithManager(mgr); err != nil {
+			setupLog.Error(err, "Failed to create controller", "controller", "Group")
+			os.Exit(1)
+		}
+
 		if gatewayAPIEnabled {
 			if err = (&controller.GatewayClassReconciler{
 				Client: mgr.GetClient(),