* refine paddle inference api
Co-authored-by: Nnhzlx <nhzlx.dragon@gmail.com>

* remove the obsolete cmake options, test=develop

* remove unittests, test=develop

* update anakin-engine interfaces for content-dnn

test=develop

* support only-gpu mode of Anakin

modify eltwise parse

test=develop

* modification for thread-safe

test=develop

* Integrated template instance

test=develop

* increase template parameters

test=develop

* support MLU predictor

test=develop

* update anakin cmake files

test=develop

* update TargetWrapper::set_device

* update the initialization of anakin subgraph

test=develop

* use the default constructor of base class

test=develop

test=develop

This patch also refactors conv+bn (includes changes from PR
https://github.com/PaddlePaddle/Paddle/pull/13926)
updated to use the mkldnn-placement-pass.

test=develop

* add MKL-DNN placement pass

This patch also refactors conv+bn (includes changes from PR
https://github.com/PaddlePaddle/Paddle/pull/13926)
updated to use the mkldnn-placement-pass.

test=develop

* remove redundant pass list

* add comment on the default first pass

* fix test for conv+relu mkldnn fuse

test=develop

- add naive executor
- fix concurrency performance issue

  extended test_text_classification ot use new op

* anakin support x86

* fix code style

* add anakin ditu cnn demo

* add timer

* add rnn

* fix inference_anakin_cnn/rnn_test compile error

* make anakin_rnn_tester run

* add anakin_enable_op_time option

* update api/CMakeLists.txt

* enlarge the max_batch_size in anakin.config

* update with comments

* make fc fuse work with ditu rnn
* add ditu rnn data download to CMAKE

* hide misc APIs

* update

* fix transformer test

* update API.spec