Release v1.4.0

DatabaseAdmin classes retain a reference to the Async/Database instance that spawned it, if any

• introduced a spawner_database parameter to database admin constructors
• database admin can retroactively set the db's working namespace upon creation of same
• Idiom database = client.get_database(...); database.get_database_admin().create_namespace("the_namespace", update_db_namespace=True)

Database (and AsyncDatabase) classes admit null namespace:

• default to "default_namespace" only for Astra, otherwise null
• as long as null, most operations are unavailable and error out
• a use_namespace method to (mutably) set the working namespace on a database instance

AstraDBDatabaseAdmin class is fully region-aware:

• can be instantiated with an endpoint (also id parameter aliased to api_endpoint)
• requires a region to be specified with an ID, unless auto-guess can be done

VectorizeOps: support for find_embedding_providers Database method

Support for multiple-header embedding api keys:

• EmbeddingHeadersProvider classes for embedding_api_key parameter
• AWS header provider in addition to the regular one-header one
• adapt CI to cover this setup

Testing:

• restructure CI to fully support HCD alongside Astra DB
• add details for testing new embedding providers