Add support for properties in hybrid search

[dirkkul]

With 1.19.0 Weaviate supports properties in hybrid search: The BM25-part of hybrid only searches the given properties.

The properties should be added to the HybridBuilder and the resulting GraphQL query then needs to look like this:

hybrid:{query:\"hello\",  properties: ["prop1", "prop"] ...more options...}

The parameter is optional and not supplying it results in all properties being searched.

Example python PR

[jiamliang]

Waiting for a new release.