Make Vyriad qdrant optional

[minump]

VectorDB has 2 QdrantClient - only with QDRANT_URL and another with VYRIAD_QDRANT_URL . If VYRIAD_QDRANT_URL is not present,

ai-ta-backend/ai_ta_backend/database/vector.py

Line 30 in 167e00c

self.vyriad_qdrant_client = QdrantClient(url=os.environ['VYRIAD_QDRANT_URL'],

this will throw an error.
This is problematic for the self-hosted version as there is no vyraid vectorDB needed.

As a temporary fix : have the vyriad vectorDB in a try-catch code similar to cropwizard.
Later explore better options.