create new file system (based on Orchard)

zero.Core/FileStorage/FileSystemException.cs

@@ -0,0 +1,10 @@
+namespace zero.FileStorage;
+
+public class FileSystemException : Exception
+{
+  public FileSystemException() { }
+ 
+  public FileSystemException(string message) : base(message) { }
+
+  public FileSystemException(string message, Exception innerException) : base(message, innerException) { }
+}