Cleanup after plan B

[vividfog]

1. Improved error handling for failed API requests using try...except blocks and exiting the script with an error message
2. Enhanced error handling for failed parsing of XML and JSON responses
3. Added additional error handling for SQLite database connection issues
4. Refactored data processing functions in fingrid.py, llm.py, sahkotin.py, and sql.py to handle exceptions and exit with an error message when necessary
5. Removed joblib import and model persistence logic from train_model function in train.py
6. Updated the train_model function in train.py to return the trained Random Forest model (rf) along with evaluation metrics
7. Other minor adjustments for better error handling and script execution.