Add additional tests for the optical throughput calibration using muon rings

Summary

• Need to test if proper metadata is uploaded to the DB.
• Need to test how the tables with optical throughput calibration values are created
• Add test for many telescopes (currently the functionality is tested only for one telescope)
• Add proper tests for exception handling (better to add them after refactoring of main calibrator class)

What is the expected correct behavior?

New unittests that check new functionality should be created and passed.