Implement database connection pooling with context manager pattern

- Added DBUtils PooledDB for intelligent connection pooling
- Created db_pool.py with lazy-initialized connection pool (max 20 connections)
- Added db_connection_context() context manager for safe connection handling
- Refactored all 19 database operations to use context manager pattern
- Ensures proper connection cleanup and exception handling
- Prevents connection exhaustion on POST requests
- Added logging configuration for debugging

Changes:
- py_app/app/db_pool.py: New connection pool manager
- py_app/app/logging_config.py: Centralized logging
- py_app/app/__init__.py: Updated to use connection pool
- py_app/app/routes.py: Refactored all DB operations to use context manager
- py_app/app/settings.py: Updated settings handlers
- py_app/requirements.txt: Added DBUtils dependency

This solves the connection timeout issues experienced with the fgscan page.

py_app/requirements.txt

@@ -4,6 +4,7 @@ Werkzeug
 gunicorn
 pyodbc
 mariadb
+DBUtils==3.1.2
 reportlab
 requests
 pandas