Integrate fft-conv-pytorch

[mpariente]

Might be much faster (and more precise) for longer FFT kernels.

See here.

[popcornell]

I see there is also a rather convenient FFTConv layer which is handy IMO. Apart from this, is it the same than torchaudiomentation convolve ?
https://github.com/asteroid-team/torch-audiomentations/blob/71c27d8206a0850640525b97a7241eb4625d755b/torch_audiomentations/utils/convolution.py#L40

[mpariente]

We'd have to check both implementations more carefully. There is also an implementation in julius I believe so we'll have to choose from those options.

Note, convolve in torch-audiomentations comes from pyro, I opened an issue there to link to the original code.