Feature: Add Native SQLAlchemy Dialect Support

[saquibsaifee]

Currently, presto-python-client does not natively support SQLAlchemy. Users looking for ORM integration often rely on PyHive, which is now in maintenance mode (donated to Apache Kyuubi) and may not support newer Presto features.

This issue proposes adding a native SQLAlchemy dialect directly into presto-python-client.

Goals:

1. Provide a built-in presto:// dialect.
2. Support standard SQLAlchemy create_engine usage.
3. Support basic data types and complex types (ARRAY, MAP, ROW).
4. Remove the need for external legacy dependencies for basic ORM support.

I have working code for this based on the existing dbapi and patterns from trino-python-client, and will submit a PR shortly.