Add cimfs differ and snapshotter

Details about CimFs project are discussed in #8346

Signed-off-by: Amit Barve <ambarve@microsoft.com>

vendor/github.com/Microsoft/hcsshim/internal/hcs/schema2/layer.go

@@ -9,6 +9,13 @@
 
 package hcsschema
 
+type FileSystemFilterType string
+
+const (
+	UnionFS FileSystemFilterType = "UnionFS"
+	WCIFS   FileSystemFilterType = "WCIFS"
+)
+
 type Layer struct {
 	Id string `json:"Id,omitempty"`
 

vendor/github.com/Microsoft/hcsshim/internal/hcs/schema2/registry_hive.go

@@ -0,0 +1,13 @@
+package hcsschema
+
+// NOTE: manually added
+
+type RegistryHive string
+
+// List of RegistryHive
+const (
+	RegistryHive_SYSTEM   RegistryHive = "System"
+	RegistryHive_SOFTWARE RegistryHive = "Software"
+	RegistryHive_SECURITY RegistryHive = "Security"
+	RegistryHive_SAM      RegistryHive = "Sam"
+)

vendor/github.com/Microsoft/hcsshim/internal/hcs/schema2/registry_key.go

@@ -10,7 +10,7 @@
 package hcsschema
 
 type RegistryKey struct {
-	Hive string `json:"Hive,omitempty"`
+	Hive RegistryHive `json:"Hive,omitempty"`
 
 	Name string `json:"Name,omitempty"`
 

vendor/github.com/Microsoft/hcsshim/internal/hcs/schema2/registry_value.go

@@ -14,7 +14,7 @@ type RegistryValue struct {
 
 	Name string `json:"Name,omitempty"`
 
-	Type_ string `json:"Type,omitempty"`
+	Type_ RegistryValueType `json:"Type,omitempty"`
 
 	//  One and only one value type must be set.
 	StringValue string `json:"StringValue,omitempty"`

vendor/github.com/Microsoft/hcsshim/internal/hcs/schema2/registry_value_type.go

@@ -0,0 +1,17 @@
+package hcsschema
+
+// NOTE: manually added
+
+type RegistryValueType string
+
+// List of RegistryValueType
+const (
+	RegistryValueType_NONE            RegistryValueType = "None"
+	RegistryValueType_STRING          RegistryValueType = "String"
+	RegistryValueType_EXPANDED_STRING RegistryValueType = "ExpandedString"
+	RegistryValueType_MULTI_STRING    RegistryValueType = "MultiString"
+	RegistryValueType_BINARY          RegistryValueType = "Binary"
+	RegistryValueType_D_WORD          RegistryValueType = "DWord"
+	RegistryValueType_Q_WORD          RegistryValueType = "QWord"
+	RegistryValueType_CUSTOM_TYPE     RegistryValueType = "CustomType"
+)