Add PG Hydra support and update configuration options

[AshAnand34]

Adds support for PG Hydra from Issue #27

• Introduced PG Hydra configuration options in CONFIGURATION.md, including host, port, database, username, and password.
• Updated CLI options to include PG Hydra and sharded variants in database selection.
• Enhanced the performance tester to support PG Hydra and sharded configurations.
• Added PG Hydra database management functionality, including connection handling, database creation, and sharding setup.
• Updated documentation to reflect new PG Hydra features and usage instructions.

This enhances the testing framework by allowing users to leverage PG Hydra for performance testing alongside existing databases.