[FEA]Need driver class for the gQuant task graph

[yidong72]

Is your feature request related to a problem? Please describe.
The task graph can be run in different contexts. Some of the hyper-parameters used inside the nodes are coming from this context. Currently, gQuant is not context-aware.

Describe the solution you'd like
Build a driver class to define the running environment for the graph. So the context-related information can be queried by the graph.

[avolkov1]

Ideas behind motivation for a "driver".

Driver —A Driver is a special "Node" which runs a TaskGraph with some context or perhaps just adds context to a TaskGraph. The Driver can orchestrate some scheduler such as Dask or Ray or similar distribution framework for a TaskGraph. The Driver could manipulate a task graph perhaps by having iterations and loops, substituting some global shared variables between the nodes in the task graph, etc. Any logic that is not simply expressed as a TaskGraph itself can be placed in a driver.