Reduce the dependencies of nkululeko

[felixbur]

Currently, a nkululeko environment is quite large and needs numerous packages to be installed. Would be great to check for each of them whether they could be replaced or somehow at least reduced in size.

[bagustris]

I only found that currently, the only thing works is to replace audiofile with torchaudio since the latter completely can be used in place of audiofile, but it needs a lot of work and the (size) reduction may be not significant.