* Merge hapi into Paddle

Hapi is a high level API for training and inference.
The main modules include Model, Loss, Metrics, Dataset.
Also includes common modules and models in NLP and computer vision, such as BERT, ResNet.

These modules are developed by:
0YuanZhang0, guoshengCS heavengate, LielinJiang, qingqing01, xyzhou-puck huangjun12, wangxiao1021, zhangyang.

* add new macro BOOST_GET_SAFELY & unittests, test=develop

* add different macro type, test=develop

* fix get macro type in executor, test=develop

* four macro part change backup

* using one macro for all case, test=develop

* revert attribute change, test=develop

* change to three func to solve gcc4.8 bug, test=develop

* polish some details, test=develop

test=develop

* Optimize the error messages of paddle CUDA API, test=develop

* fix the error messages of paddle CUDA API, test=develop

* Refactoring PADDLE_ENFORCE_CUDA_SUCCESS, and apply to curand/cudnn/cublas/NCCL,test=develop

* remove build_ex_string,test=develop

* merge conflict,test=develop

* add ccache

* test=develop

* enrich count enforce scripts, test=develop, test=document_fix

* add usage & result, test=develop, test=document_fix

* install mpi in Dockerfile for coverage ci in xiaolvyun
* test=develop

This reverts commit 23baf865.

* test=cpu

* test=cpu

* test=py2gcc8

* test=py2gcc8

* test=py2gcc8

* test=py2gcc8

* test=py2gcc8

* test=py2gcc8

* test=py2gcc8

* test=develop;test=document_fix;test=py2gcc8

* add dygraph parallel env doc, test=develop

* polish details, test=develop, test=document_fix

* fix examples error in other apis, test=develop

* fix more example error in other api, test=develop

* add white list for gpu examples, test=develop, test=document_fix

* reproduce match error, test=develop, test=document_fix

* fix mismatch error, test=develop, test=document_fix

* add no_grad_set value check in op_test, test=develop

* update ops list, test=develop