Add batch_create_links method in weaviate hook

[sjyangkevin]

Motivation

Users can create links between objects through cross-references using this method.

Close #42568

Test

Add the following 2 test cases

• Ensure add_reference is called the right number of times.
• Ensure the retry mechanism is working
• A DAG is created to connect to Weaviate and links existing objects in two different collections.

Testing DAG code

@task()
def batch_create_links():
    from airflow.providers.weaviate.hooks.weaviate import WeaviateHook
    from weaviate.classes.query import QueryReference
    import pandas as pd

    weaviate_hook = WeaviateHook()

    weaviate_hook.batch_create_links(
        collection_name="JeopardyQuestion",
        data=pd.DataFrame.from_dict(
            {
                "from_uuid": ["5b118d91-7006-444f-a028-08372f1e7356", "00d38b07-ebd7-484a-a75c-2fa37ecfb29d"],
                "to_uuid": ["b801e25e-6c86-4ad6-a5c9-d14994375a71", "b0c80fc4-cc87-42a6-9324-f2e663d67266"],
                "from_property": ["hasCategory", "hasCategory"]
            }
        ),
        from_property_col="from_property",
        from_uuid_col="from_uuid",
        to_uuid_col="to_uuid"
    )

    collection = weaviate_hook.get_collection("JeopardyQuestion")

    response = collection.query.fetch_objects(
        return_references=QueryReference(
            link_on="hasCategory",
            return_properties=["category"]
        )
    )
    print(len(response.objects))
    print(response)

Test Output

Before adding the links, the references property in the QueryReturn is an empty dictionary.

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