fix: parametrize opensearch and docling url on langflow flows

[lucaseduoli]

This pull request improves the configuration and environment variable management for OpenSearch and Docling services across Docker, Helm, and flow definitions. The main focus is to make service URLs and credentials more flexible and environment-driven, enhancing deployment portability and maintainability. It also updates the TUI diagnostics to use these environment variables dynamically.

Configuration and Environment Variable Improvements:

• Added OPENSEARCH_HOST, OPENSEARCH_PORT, OPENSEARCH_URL, and DOCLING_SERVE_URL as environment variables in both docker-compose.yml and Helm templates, allowing for dynamic configuration of service endpoints. [1] [2]
• Updated the list of environment variables exposed to flows in both docker-compose.yml and helm/openrag/values.yaml to include OPENSEARCH_URL and DOCLING_SERVE_URL. [1] [2]

Flow Definitions:

• Changed the default values for opensearch_url and api_url in all relevant flow JSON files to reference the new environment variables (OPENSEARCH_URL, DOCLING_SERVE_URL) instead of hardcoded URLs. Also set these fields to load from the database. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]

Diagnostics and Tooling:

• Refactored the TUI diagnostics (src/tui/screens/diagnostics.py) to construct the OpenSearch URL from environment variables (OPENSEARCH_HOST, OPENSEARCH_PORT) rather than using hardcoded values, ensuring tests and checks run against the correct endpoint in any environment. [1] [2] [3] [4] [5]

Closes #807

[edwinjosechittilappilly]

Testing
Good the integration tests passed!