Move cloud metadata packages and kubernetes resources marshaling to internal

Decouples cloud provider metadata packages from kubernetes related code

Signed-off-by: Malte Poll <mp@edgeless.systems>

internal/kubernetes/configmaps.go

@@ -0,0 +1,18 @@
+package kubernetes
+
+import (
+	k8s "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+)
+
+// ConfigMaps represent a list of k8s ConfigMap.
+type ConfigMaps []*k8s.ConfigMap
+
+// Marshal marshals config maps into multiple YAML documents.
+func (s ConfigMaps) Marshal() ([]byte, error) {
+	objects := make([]runtime.Object, len(s))
+	for i := range s {
+		objects[i] = s[i]
+	}
+	return MarshalK8SResourcesList(objects)
+}