Callable-based Group class

[davbzn]

I want to propose a change in the Group class.
At the moment, this class is based purely on string commands to set/get the grouped parameters.
I believe QCoDeS would benefit from a more general implementation of this class that accepts generic callables.
The use case would be those instruments that do not rely on string commands and have a set/get function targetting a group of parameters.

In this view, the current implementation of the Group class would be a specific case in which the callable is the write/query function of the instrument with a command string.

Would this be of interest to the QCoDeS community?