Add scale_to_uV preprocessing

[h-mayorquin]

The justification from:

#2958 (comment)

Now that I think about it myself what I would like is to have a preprocessing called scale_to_uV that which allows me to write:

recording_in_uV = spre.scale_to_uV(recording=raw_recording)
si.write_binary_recording(recording_in_uV, file_paths=file_path, dtype=dtype, **job_kwargs)

I think this is both concise while at the same time generalizes to situations beyond write_binary_recording. What do you think @jnjnnjzch, do you feel this would make the API more in line with your concept of elegance?

I actually would like your take on this @JoeZiminski as you have been thinking about preprocessing. My thinking here is that I think is better to combine simple functions and apply them flexibly depending on the situation at hand rather than adding a new parameter to each of the core functions for every situation. The latter also has the downside of making the core functions more difficult to optimize and document. See here for another instance where I think this question arises: #2985. I recognize there might be performance limitations that might limit this approach but I would rather take it as a baseline.