Introduce containerd-shim-runhcs-v1 on Windows

Implements the containerd-shim-runhcs-v1 shim on Windows for the runtime
v2 shim API.

Signed-off-by: Justin Terry (VM) <juterry@microsoft.com>

vendor/github.com/Microsoft/hcsshim/internal/wclayer/layerid.go

@@ -0,0 +1,13 @@
+package wclayer
+
+import (
+	"path/filepath"
+
+	"github.com/Microsoft/hcsshim/internal/guid"
+)
+
+// LayerID returns the layer ID of a layer on disk.
+func LayerID(path string) (guid.GUID, error) {
+	_, file := filepath.Split(path)
+	return NameToGuid(file)
+}