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/cloud/gcp/role.go

@@ -0,0 +1,19 @@
+package gcp
+
+import (
+	"github.com/edgelesssys/constellation/bootstrapper/role"
+)
+
+const roleMetadataKey = "constellation-role"
+
+// extractRole extracts role from cloud provider metadata.
+func extractRole(metadata map[string]string) role.Role {
+	switch metadata[roleMetadataKey] {
+	case role.ControlPlane.String():
+		return role.ControlPlane
+	case role.Worker.String():
+		return role.Worker
+	default:
+		return role.Unknown
+	}
+}