Refactor in such a way that multiple connections can be opend by using handle

[achim1]

By making it object oriented, we broke the functional style of the original CAEN library. This currently prevents us from having multiple, independent CaenN6725 objects. We are currently helping ourselves with a helper class, but we could separate the config part from the constructor. This would allow to have constructor only with the handle and thus open multiple connections

[achim1]

Task completed