Support for data format NHWC in convolutional layers

[MathiesW]

Hello, First of all, thank you for your great work! I noticed that Equinoxs' convolutional layers use NCHW data format, which, according to Nvidia Tensor Layout, is not optimal for Tensor cores on modern day GPUs. Changing the (default) data format from NCHW to NHWC hence may benefit performance of convolutional operations.