Use custom resources for Ray to schedule a task on a concrete node

[YarShev]

It would be helpful to provide an ability to specify custom resources for Ray to be able to schedule a task on a concrete node. E.g., one can provide a related config to use it when scheduling a remote task.

How it could work

import modin.pandas as pd
import modin.config as cfg

cfg.RayInitCustomResources.put({"special_hardware": 1.0})
cfg.RayTaskCustomResources.put({"special_hardware": 0.25}) # this setting will limit the number of tasks running in parallel to 1.0 / 0.25 = 4.0

df = pd.DataFrame(...)
df.abs() # 4 remote tasks will be running concurrently

# or you could limit the number of tasks running in parallel for a certain operation using context
with cfg.context(RayTaskCustomResources={"special_hardware": 0.5}):
    df.abs() # 2 remote tasks will be running concurrently