[FEA] Add a find_peaks function

[cliffburdick]

find_peaks is a useful function for giving the user a powerful interface to find one or more peaks in a signal based on some criteria. The SciPy find_peaks has many features, some of which aren't used as much. This issue is for implementing an MVP of this function with the distance, threshold, and height parameters.

https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.find_peaks.html

[deanljohnson]

I would be very interested in a well optimized 2d version of this function.

I have implemented something previously, but I really doubt it is optimal. I used cub::DeviceSelect::Flagged with a custom iterator that returned true if an index was a local optima (by checking all adjacent values). It would not support a distance parameter, but could handle the threshold and height parameters easily.