mschwoer

re-active multicova backend, which was disabled here https://github.com/MannLabs/alphapeptstats/pull/329/files

**Describe the bug** Hey, I rarely get `ZeroDivisionError` on some blank files, mb just adjust the logging message? `len(df_nonnans.columns)/len(df.columns) if len(df.columns) else -1` ? ``` [2024-08-24, 23:19:08 UTC] {ssh.py:529} INFO...