Add File properties "nonce" and "key"

EdgeAndPropertyHierarchy/blake2b/blake2b.json

-{
-  "description": "The blake2b hash of a resource.",
-  "type": "string"
-}
\ No newline at end of file

EdgeAndPropertyHierarchy/nonce/nonce.json

+{
+  "description": "A cryptographic nonce https://en.wikipedia.org/wiki/Cryptographic_nonce",
+  "type": "string"
+}

TypeHierarchy/Item/File/File.json

 {
-  "description": "Any type of file that can be stored on disk.",
+  "description": "Any file that can be stored on disk.",
   "properties": [
-    "blake2b",
     "sha256",
+    "nonce",
+    "key",
     "filename"
   ],
   "relations": {
@@ -17,4 +18,4 @@
   },
   "foregroundColor": "#ffffff",
   "backgroundColor": "#93c47d"
-}
\ No newline at end of file
+}