Feat: improve environment configuration and Docker support

[thamudi]

This pull request introduces significant updates to the project configuration and deployment setup. Key changes include a comprehensive overhaul of environment variables, the addition of a local Dockerfile for the frontend, and improvements to the compose.yaml file to streamline container management and enhance modularity.

Environment Configuration Updates:

• .env.sample: Expanded environment variables to include detailed configurations for server, database, Redis, mail client, and third-party integrations. This improves clarity and centralizes configuration management.

Docker and Deployment Enhancements:

• Dockerfile.local: Added a new Dockerfile for the frontend, specifying the Node.js version, build steps, and runtime commands to simplify local development.
• compose.yaml: Updated the web service to use the new Dockerfile, added .env for environment variable management, and improved volume handling to ensure proper dependency usage.
• compose.yaml: Modified the postgres service to use .env for environment variables and added a named volume (postgres-data) for persistent database storage.