No error handling for file operations

[michaelsaki]

🐛 Summary

The source code opens several files for reading and writing without implementing explicit error handling for cases where files might not exist, lack permissions, or encounter other I/O errors.

This is the case for the following files:

create_sld_to_agency_name_and_id_mapping.py
pshtt_csv2mongo.py
sslyze_csv2mongo.py
trustymail_csv2mongo.py

Expected behavior

Add error handling around file operations to handle potential errors gracefully. Provide meaningful error messages to help diagnose issues when they occur.