Add architecture: Convolutions & Kernel matrices

[mvrahden]

Is your feature request related to a problem? Please describe.
Add convolutions via filter functions (Kernel) to learn from multidimensional data.

Describe the solution you'd like
See convolutional neural networks (CNN).
A convolutional layer network that breaks the multidimensional data down (as a form of pre-processing) into a vector, which can then be fed into a NN-architecture.

Describe alternatives you've considered
none

Additional context
none