Before Image in Streams API

Added support for before image in the Streams API. Users can configure subscription streams to include the before images of streamed operations.

Streaming Transactions

Added support for streaming by transaction in the Streams API. A user can now configure subscription streams to stream transactions instead of individual put and delete operations.

User-supplied record metadata

Added an experimental version of user supplied metadata. Users can add their own metadata, formatted as a JSON construct, to write operations and persistently store that information alongside the record. Records can subsequently be filtered using a new system defined function, row_metadata(). Before using this experimental feature, see the Known Issues section below to understand its limitations. We would appreciate your feedback on the usefulness of this feature and APIs and encourage you to post your feedback in the NoSQL GitHub repository.