Add new vectorization strategy visualization
This merge request improves logging in the vectorization strategies by providing another stringify version that makes it possible to see quickly what type of vectorization strategy was used. It shows the different inout keys of the scalar sum factorization kernels (by numbers 1, 2,...), padding (by 0) and splitting by 's'.
['1', 's', '2', 's']: Two input, that get broadcasted into the lower and
upper part with a splitting of 2.
['1', '1', '1', '0']: Combine three sum factorization kernels with the same
input and use padding in the end.
['1', 's', 's', '0']: One scalar kernel with splitting of three and padding
in the end.