Improve code quality in the Physical Library catalogue code
As mentioned in #462 (closed), we want to use the refactoring of the CTA catalogue Physical Library code as a reference for the Recycling Tape File (and all the other CTA Catalogue functions, in the near future).
Therefore, before performing these changes, it's important that we guarantee that the Physical Library code follows all the best practices. In particular, by not having any of the code smells identifies by sonarcloud.
Tasks:
- Fix issues identified by Sonarcloud
- Simplify exception handling mechanism