Create an NXQL Hint to use AWS ES similarity search based on KNN

Since AWS ES 7.7 (which is working with Nuxeo 11.4), it is possible to define `knn_vector` the equivalent of the `dense_vector` in the Elasticsearch non-oss version.

KNN search can be used for similarity search

https://docs.aws.amazon.com/elasticsearch-service/latest/developerguide/knn.html

The goal of this ticket is to demonstrate that we can do a similarity search in Nuxeo >= 11.4 in NCO env.

This should be about defining a custom mapping and contributing an NXQL Hint where we can choose the distance to use (cosine being the default).