Run schema testing for all protocols once

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• [x] prot-ak.xml
• [x] prot-fk.xml
• [ ] prot-ek.xml

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LXML started throwing weird errors about (nonexistant) ID duplicates, so I did the validation in scala instead https://github.com/swerik-project/parlaclarin-validation

All record files were valid parla-clarin.