Add basic convolution kernels and methods

[bmorris3]

To do:

• [ ] add docs
• [ ] add tests
• [ ] @Hoeijmakers – compare against convolutions in tayph

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[bprinoth]

@Hoeijmakers I am trying to test these two kernels by reproducing what tayph.operations.blur_rotate does (which I think should be doing the same if both of these rotations are applied after each other).

Tayph produces these cute little wings, looks a bit like batman, but the combination of Gauss and then rot kernel does not. Any idea what I am missing?

[Hoeijmakers]

I think that you have all that's necessary to figure out the difference ;)

[bprinoth]

@Hoeijmakers You were indeed right about that ;)