support for attachments keys

load existing items and set attachments on key update

src/Core/Models/Api/CipherAttachmentModel.cs

@@ -0,0 +1,21 @@
+using Bit.Core.Models.Data;
+using Bit.Core.Utilities;
+
+namespace Bit.Core.Models.Api
+{
+    public class CipherAttachmentModel
+    {
+        public CipherAttachmentModel() { }
+
+        public CipherAttachmentModel(CipherAttachment.MetaData data)
+        {
+            FileName = data.FileName;
+            Key = data.Key;
+        }
+        
+        [EncryptedStringLength(1000)]
+        public string FileName { get; set; }
+        [EncryptedStringLength(1000)]
+        public string Key { get; set; }
+    }
+}