Add the ability to set the owner of objects when calling _save_spark_df_to_object_store()

[max-509]

Add the ability to set the owner of objects when calling _save_spark_df_to_object_store()

[kira-lin]

Hi @max-509 , thanks for using RayDP!
In this case, you can assign ownership to RayDPMaster, and use raydp.stop_spark(cleanup_data=False) to stop the session and free up the resources. By setting cleanup_data to False, RayDPMaster is actually not killed, so the data is still accessible.

But yes, your suggestion makes sense, ownership should be able to be assigned to a user specified actor. This should be very easy, are you willing to submit a PR?