Dev build and infer ctx (#2089)

* add job_build_and_infer_ctx interface

* lbn_with_split_hint

* fix maybe macro

* fix signature of Maybe<T>::Error()

* job_build_and_infer_if

* add c_api_util wrapper for job_build_and_infer_ctx

* implement python/job_build_and_infer interface

* CurJobBuildAndInferCtx_AddPlacementGroup

* BuildJobAndInferCtx  and  Mgr  c++ implement (#2074)

* job_build_and_infer_ctx_mgr

* refine interface of infer_ctx_mgr

* JobBuildInferCtx set job conf; add and refine error type

* revert job.proto

* half impl of add op in build_infer_ctx

* generate op produced empty logical blob desc ; infer out blob desc interface

* job_build_and_infer_ctx VERSION 1

* add InferOutBlobDesc for conv op; remove record_piece_size in interface op

* maybe return

* job_set hold by job_build_and_infer_ctx_mgr

* check placement when infer ctx mgr leave cur job

* Global New/Delete JobBuildAndInferCtxMgr

* add JUST when ctx add op

* remove unused job_conf.arg_op_name

* fix bugs caused by python new api

* fix bugs caused by lack of Global<JobDesc>

* fix bugs caused by new api

* refactor compiler.Compile

* merge dev_python

* remove unused message proto

* rename api