Description

This PR adds automatic generation of database URLs with proper validation to the SQLAlchemy configuration. It implements a custom PostgresDsn class that extends Pydantic's AnyUrl, providing validation of PostgreSQL connection strings with support for various PostgreSQL-specific drivers.

The implementation includes two main features:

1. Auto-generation of connection URLs when component parameters (username, password, host, port, database) are provided
2. Extraction of component parts from a provided URL to populate missing fields

This makes the configuration more flexible and robust, allowing users to specify either individual components or a complete connection string.

Type of change

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How Has This Been Tested?

• Tested URL generation with all components provided
• Tested URL validation with valid PostgreSQL schemes
• Tested URL validation with invalid schemes
• Tested component extraction from valid URLs
• Tested with and without password in the connection string

Sample code for testing:

# Test with individual components
db_config = SqlAlchemyConfig(
    USERNAME="postgres", 
    PASSWORD="password123", 
    HOST="localhost", 
    PORT=5432, 
    DATABASE="mydb"
)
assert db_config.DB_URL is not None

# Test with connection string
db_config = SqlAlchemyConfig(
    DB_URL="postgresql+psycopg://user:pass@dbhost:5432/otherdb"
)
assert db_config.USERNAME == "user"
assert db_config.PASSWORD == "pass"
assert db_config.HOST == "dbhost"
assert db_config.PORT == 5432
assert db_config.DATABASE == "otherdb"

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my feature works
• New and existing unit tests pass locally with my changes

Additional context

This implementation follows Python 3.13 conventions by using Union syntax (|) and proper type hints throughout.
Resolves #28