* Move api(lgamma) from legacy_api.yaml to api.yaml

* Move api(lgamma) from legacy_api.yaml to api.yaml

* Move api(lgamma) from legacy_api.yaml to api.yaml

* modify code style

* add x to X mapping

* add definition of lgamma

* delete redundant lgamma definitions

* Modify code comments

* Modify ops.py code format

* add lgamma  single test and lgamma api in fluid

* Optimized lgamma unittest