Add inference.stream_inference and inference.update

Relates to https://github.com/elastic/elasticsearch-specification/issues/3377, https://github.com/elastic/elasticsearch/pull/119472 This PR adds a missing specification based on https://www.elastic.co/guide/en/elasticsearch/reference/master/stream-inference-api.html and https://www.elastic.co/guide/en/elasticsearch/reference/master/update-inference-api.html