Weaviate 1.16 release

Weaviate 1.16 introduces new filter operators, distributed backups, ref2vec-centroid module, Node Status API, support for Azure-issued OIDC tokens, and patch releases ready sooner. The new filter operators allow users to filter data based on null values or array lengths. Distributed backups enable backup of objects stored in multi-shard configuration across multiple nodes. Ref2vec-centroid module calculates a mean vector of referenced objects. Node Status API checks the health of running clusters, and support for Azure-issued OIDC tokens allows authentication with Azure, Keycloak, or Dex OIDC tokens. Patch releases are now published as soon as new important fixes are available.