Switch from obsolete ogg.vorbis library to python-soundfile

pyvorbis is no longer available after debian Buster.

Associated clientdata pipeline: https://git.themanaworld.org/specing/clientdata/-/commits/test_testxml_update

Requires packages updated in clientdata as in that branch. Perhaps better to shift .tools/testxml.sh into tools repo.

Squashed with:
* Remove other method left commented out and untested

* Why specify specific exception type when we can just handle them all?

* Alright, ancient (10.1-3) SoundFile lib has no SoundFileError yet

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