move strategic merge patch transformer to a builtin transformer

pkg/ifc/transformer/factory.go

@@ -1,17 +0,0 @@
-/// Copyright 2019 The Kubernetes Authors.
-// SPDX-License-Identifier: Apache-2.0
-
-// Package patch holds miscellaneous interfaces used by kustomize.
-package transformer
-
-import (
-	"sigs.k8s.io/kustomize/v3/pkg/resource"
-	"sigs.k8s.io/kustomize/v3/pkg/transformers"
-)
-
-// Factory makes transformers that require k8sdeps.
-type Factory interface {
-	MakePatchTransformer(
-		slice []*resource.Resource,
-		rf *resource.Factory) (transformers.Transformer, error)
-}