Add streaming mode to PTFs

There are a set of use cases where the Table Function can operate on a Partition row by row or on a subset(window) of rows as it is being streamed to it.

• Windowing has couple of use cases of this:processing of Rank functions, processing of Window Aggregations.
• But this is a generic concept: any analysis that operates on an Ordered partition maybe able to operate in Streaming mode.

This patch introduces streaming mode in PTFs and provides the mechanics to handle PTF chains that contain both modes of PTFs.
Subsequent patches will introduce Streaming mode for Windowing.