Bug fixing before tagging

Summary

This fixes some errors with the CTA Catalogue schema, and it's migration scripts, before tagging v15.0.

References

Pipeline testing this CTA Catalogue schema version with the CTA project:

• https://gitlab.cern.ch/cta/CTA/-/pipelines/7856764

It passes all tests, including liquibase migration.

CTA Catalogue v15.0 tagging issue:

• CTA#801 (closed)