Add initial CI/CD pipeline for database repository

[poojan644]

Created an initial GitHub Actions workflow for the database repository.

Current pipeline includes:

• Repository checkout
• Repository structure validation
• DDL directory validation
• DML directory validation
• SQL file discovery

This is an experimental first version intended to establish a basic CI/CD workflow for future enhancements.

[poojan644]

Implemented an initial CI/CD pipeline for the database repository.

The workflow currently validates the repository structure, verifies the DDL and DML directories, and checks for SQL files.

The pipeline was tested successfully, and the workflow completed without errors.

[poojan644]

Implemented the initial database CI/CD pipeline with repository structure validation, SQL file validation, PostgreSQL/PostGIS test environment setup, required database role and schema initialization, and database script execution testing. CI checks are now passing.