Dask default's to a disk-based shuffle even thought we're using a distributed scheduler, which appears to be resulting in dropped data since the filesystem isn't shared across nodes. Dask Distributed manually sets the shuffle algorithm in the global config to the task-based shuffle, which the Dask-on-Ray scheduler should probably do as well.
This PR adds a Dask config helper, `enable_dask_on_ray`, that sets Dask-on-Ray as the default scheduler along with changing the default shuffle to a task-based shuffle. The shuffle method can still be overridden by the user by manually specifying `df.set_index(shuffle="disk")`.
## Why are these changes needed?
- Since broadcasting is moving to grpc, introducing the option to increase the client side thread number
- For hybrid schedule, ignore the threshold if gcs based actor scheduler is enabled
With these fixing, actor creation rate > 600actor/s vs ~ 140 actor/s
## Related issue number
