[Feature implementation] Implement AudioQnA pipeline for Enterprise RAG based on OPEA with tests

[aalbersk]

Attention! Implementing this feature would require to use internal_main branch.

Based on AudioQnA implemented in OPEA and existing pipelines in Enterprise RAG Application, implement an AudioQnA pipeline for the Enterprise RAG Application.

• If any new microservice would be required, it should be written accordingly to already existing microservices.
• The python code should follow pep8 guidelines regarding best practices.
• The pipeline should work correctly with authorization, istio and UI.
• Basic e2e tests should be implemented for the pipeline.
• [optional] Telemetry should support any new features required for the pipeline.

[pal0064]

E_RAG_TEAM3 will work on this