Acquisition mocking in Pulsar QRM

Allows the user to specify data for the dummy to return on a call to get_acquisitions. This will allow the user to use it for tests or mocking a real experiment.

It is possible to either specify the values directly or use iterators. Opted to implement classes for mocking the different acquisition behaviour even though it is possible using iterators in both cases, since that provides more flexibility if we intend to expand upon this. Plus the tests become a bit simpler.

Mocking is done within the dummy transport, which would allow to use this irrespective of which level of the driver we use (qcodes/native/scpi). I used simple wrapper functions to expose it on the dummy driver level. This part will likely have to change a bit in the restructure.

I added tests for the new classes.