Switch from containers/image to go-containerregistry (#140)

* Vendor changes for go-containerregistry switch.

* Manual changes for go-containerregistry switch.

The biggest change is refactoring the tarball unpacking.

* Pull more of container-diff out.

* More vendor removals.

* More unit tests.

vendor/github.com/Microsoft/hcsshim/createlayer.go

@@ -1,27 +0,0 @@
-package hcsshim
-
-import "github.com/sirupsen/logrus"
-
-// CreateLayer creates a new, empty, read-only layer on the filesystem based on
-// the parent layer provided.
-func CreateLayer(info DriverInfo, id, parent string) error {
-	title := "hcsshim::CreateLayer "
-	logrus.Debugf(title+"Flavour %d ID %s parent %s", info.Flavour, id, parent)
-
-	// Convert info to API calling convention
-	infop, err := convertDriverInfo(info)
-	if err != nil {
-		logrus.Error(err)
-		return err
-	}
-
-	err = createLayer(&infop, id, parent)
-	if err != nil {
-		err = makeErrorf(err, title, "id=%s parent=%s flavour=%d", id, parent, info.Flavour)
-		logrus.Error(err)
-		return err
-	}
-
-	logrus.Debugf(title+" - succeeded id=%s parent=%s flavour=%d", id, parent, info.Flavour)
-	return nil
-}