* Added a database factory function to allow reconnection when the database is closed.
* Implemented mutex locks for safe concurrent access to the database connection.
* Updated all database query methods to handle reconnection attempts on closed connections.
* Enhanced error handling for database operations across multiple providers.
* Set default query timeout to 2 minutes and enforce minimum.
* Add statement_timeout for PostgreSQL DSN.
* Implement busy timeout for SQLite with a minimum of 2 minutes.
* Enforce minimum connection timeouts of 10 minutes for server instance.
* Introduced NewConnectionFromDB function to create connections from existing *sql.DB instances.
* Added ExistingDBProvider to wrap existing database connections for dbmanager features.
* Implemented tests for NewConnectionFromDB and ExistingDBProvider functionalities.
