[Docs] Create Documentation for Fetch Sink Node

Adding a section to Streaming engine.

**Reporter**: [Vibhatha Lakmal Abeykoon](https://issues.apache.org/jira/browse/ARROW-17195) / @vibhatha

_{**Note**: *This issue was originally created as [ARROW-17195](https://issues.apache.org/jira/browse/ARROW-17195). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}

Start with the Streaming engine documentation and review the migration documentation linked in the issue for context. Identify where the Fetch Sink Node documentation belongs and add a discoverable section there; done means the node is documented in that section.

Written by the indexing model from the issue text.