[27.1] pkg/containerfs: deprecate, and add temporary aliases

There's no (known) external consumers of this, but let's add a
deprecation for the 27.1 release.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

pkg/containerfs/containerfs_deprecated.go

@@ -0,0 +1,22 @@
+package containerfs
+
+import (
+	"path/filepath"
+
+	"github.com/docker/docker/internal/containerfs"
+)
+
+// Deprecated: will be removed in the next release.
+func CleanScopedPath(path string) string {
+	if len(path) >= 2 {
+		if v := filepath.VolumeName(path); len(v) > 0 {
+			path = path[len(v):]
+		}
+	}
+	return filepath.Join(string(filepath.Separator), path)
+}
+
+// Deprecated: will be removed in the next release.
+func EnsureRemoveAll(dir string) error {
+	return containerfs.EnsureRemoveAll(dir)
+}