Richardson–Lucy deconvolution

[ashwani-rathee]

@johnnychen94 @timholy @zygmuntszpak This algorithm isn't present in JuliaImages,though it's available in most other image processing libraries
https://en.wikipedia.org/wiki/Richardson%E2%80%93Lucy_deconvolution
It's a pretty old method but still relevant.I think I could implement it here,what do you people think?

[ashwani-rathee]

I got the idea after seeing #81 #207 these PRs,although unrelated :)

[johnnychen94]

There are implementations in Deconvolution.jl, but last time I tried it, it doesn't work smoothly on our colorant arrays. Also I didn't benchmark it so don't know if it's performant. Efforts can be made to improve the status, but I'm not sure if it needs a reimplementation.

You could choose to reimplement it as an exercise, of course.