Refactor parsing of precursor data from spectrum files

[RalfG]

Added

• 🚸 If observed m/z values are available in the PSM list, always check if PSMs match with spectra

Changed

• 🚸 Do not continue if precursor info (m/z, RT, or IM) is missing for some PSMs, but not for all. This should not occur, unless something went wrong. Previously such PSMs were simply selectively removed from the dataset.
• 🔊 Clearer logging while parsing precursor info from spectrum files: Always raise error if a PSM cannot be found in the spectrum files and provide example PSM IDs from both PSM and spectrum file.
• ♻️ General refactoring of parse_spectra module