Separate endpoint from processing step logic
Firs part of code for https://github.com/huggingface/datasets-server/issues/755
Since we are going to have two different processing steps for one same endpoint:
-     Changed the dependency between endpoint-cache_kind/job_type/name in ProcessingStep
-     Moved configuration for endpoints to api service, it should not exist in other layers only in api service
Separate endpoint from processing step logic: Firs part of code for https://github.com/huggingface/datasets-server/issues/755
Since we are going to have two different processing steps for one same endpoint:
-     Changed the dependency between endpoint-cache_kind/job_type/name in ProcessingStep
-     Moved configuration for endpoints to api service, it should not exist in other layers only in api service