Add support for in-memory TPCH tests

[gabotechs]

The original DataFusion repo has the ability to run TPCH benchmarks by pre-loading the TPCH dataset in-memory. This is good because it removes disk IOs out of the picture during benchmarks.

Unfortunately, this project cannot serialize/deserialize in-memory nodes, as that would imply sending over the wire the full data loaded in memory.

This PR introduces a new node that overcomes this by storing the data in-memory in a global CACHE variable rather than in the node itself, that way, the node can be serialized and sent over the wire without baking all the in-memory data in. Upon receiving a request, the node will load the data from the global cache, which works no matter if the node was deserialized or was built natively.

An in-memory benchmark can be executed with the -m flag:

cargo run -p datafusion-distributed-benchmarks --release -- tpch -m  --path benchmarks/data/tpch_sf1

[NGA-TRAN]

The caching and warming up are good. I have a few questions to understand the when things happen

[NGA-TRAN]

LGTM