Feature gate HC by cluster feature gate object

Machine API created its own feature gate object key and diverged from all other
components expecting 'cluster' key instead. Renaming the key to 'cluster'
to minimize the confusion.

Author: ingvagabund

pkg/operator/featuresgate.go

@@ -8,7 +8,7 @@ import (
 
 const (
 	// MachineAPIFeatureGateName contains a name of the machine API FeatureGate object
-	MachineAPIFeatureGateName = "machine-api"
+	MachineAPIFeatureGateName = "cluster"
 
 	// FeatureGateMachineHealthCheck contains the name of the MachineHealthCheck feature gate
 	FeatureGateMachineHealthCheck = "MachineHealthCheck"