FRD extraction function for out-of-focus PSFs

This ticket is a specific implementation of the algorithm-development for ticket PIPE2D-630. The purpose of this ticket is to generate a function/class that takes an arbitrarily generated out-of-focus image from Neven's code and solves for its FRD. Defocused data offers the chance to learn more about the illumination of the system, among additional parameters. Determining what additional information we can learn from the out-of-focus images is as well as their corresponding uncertainties will be another result from completion of this ticket.