Publish model files as uncompressed ZIP file

[hagenw]

As we have seen in the benchmarks at audeering/audbackend#279 (comment) we can speed up downloading model files by storing them as uncompressed ZIP files. There should be not a big downside as most model files can anyway not really be compressed by ZIP.

In order to implement this feature, we need a new audbackend release, and a new audeer release which includes audeering/audeer#188.

[hagenw]

One problem here is how to change audmodel.load() as for older files (that use a compressed ZIP) we will be faster with num_workers=1, but for the newer files we will be faster with num_workers=4.

One solution would be, to store in the model header if the file is uncompressed. If a user then does audmodel.load(..., num_workers=4) we will use those workers and for a compressed file we will ignore the multiple workers.