[V1] Tracking issue for sink and source APIs for PartiQL data streams.

[rchowell]

Description

This issue is a tracking issue for several PRs in a sequence to finalize value representations along with the reader/writer implementations.

Tasks

• Package datum into SPI datum
• Updates Datum to use java.time for a sane datetime #1691
• [V1] Defines source and sink APIs for PartiQL data streams. #1655
• Add default sink/source implementations.
• Split ion/json/csv implementations from SPI package.
• Define type provider interface for different variant forms.
• Cleanup old APIs