Qdrant: Add named_vector functionality to haystack Integration

Hi,

are there any plans to integrate the capability of storing and querying multiple vectors for each point in qdrant beyond Sparse Vectors? Especially in the multimodal world this is quite an important feature and I currently can't use it w/ haystack.

Previously, if you wanted to use semantic search with multiple vectors per object, you had to create separate collections for each vector type. This was even if the vectors shared some other attributes in the payload. With Qdrant 0.10, you can now store all of these vectors together in the same collection, which allows you to share a single copy of the payload. This makes it easier to use semantic search with multiple vector types, and reduces the amount of work you need to do to set up your collections.

No files or tests are named. Start by locating the Qdrant integration entry points and its existing sparse-vector handling, then determine how collection setup and query APIs represent vectors. Done means the integration can store and query multiple named vectors in one Qdrant collection, with tests covering that behavior.