Add streaming HTTP response support to gremlin-driver

[Cole-Greer]

Summary

Adds streaming HTTP response deserialization to gremlin-driver for GraphBinary. Instead of buffering the entire HTTP response body before processing, the driver now deserializes results incrementally as data arrives from the server.

Design

Four new classes in gremlin-driver:

• ByteBufQueueInputStream — Bridges the Netty event loop and a reader thread via a BlockingQueue of ByteBufs. The event loop offers HTTP content chunks; the reader thread consumes them through standard InputStream reads.
• InputStreamBuffer — Read-only Buffer implementation backed by an InputStream. Allows existing TypeSerializer implementations to work unchanged over a streaming response body.
• GraphBinaryStreamResponseReader — Reads the GraphBinary v4 wire format one item at a time, pushing each result to the ResultSet as it is deserialized.
• HttpStreamingResponseHandler — Netty handler that replaces HttpObjectAggregator + HttpGremlinResponseDecoder in the pipeline for GraphBinary responses.

Non-GraphBinary serializers (GraphSON, custom MessageSerializer implementations) fall back to the previous aggregating pipeline.

A new cached thread pool (gremlin-driver-stream-reader) is added to Cluster for the blocking reader threads, bounded by connection pool size.