Hide passwords from log/console output

If files should be copied to a smb-share, the connection string has the form smb://<domain>\<username>:<password>@<fqdn>/<path...>. The bad thing is that the used password is written to the log output which is a NoGo for production use.

The attached patch modifies CopyTask, DeleteTask, MoveTask and SyncTask by filtering out all characters between ":" and "@" and replaces them with asterisks on the log output.