Add **OnAuthenticating** event to security

[PTKu]

I would like to request for method OnAuthenticating. Something like this I needed it in my application. There is OnUserAuthenticateSuccess but sometimes you need to check current user and compare with new one and do own scenario. By this delegate is unable to cover a required customisation... Thanks

Originally posted by @peterbarancek in https://github.com/TcOpenGroup/TcOpen/issues/468#issuecomment-1206111424