* move operators/math/math_function_* to pten/kernels/func
* namespace from `paddle::operators::math` to `pten::funcs`

* add kernel for c++ api

* fix compile bugs

* fix kunlun compile bugs

* perfect cmake

* fix compile bugs when run ci-inference

* fix compile bugs

* add non-raw kernel for fluid op

* fix compile bugs

* fix compile bugs

* fix unit test bug

* add cpu_context.

* update

* update

* update

* update

* update

* fix ci problem

* fix npu ci problem

* update

* fix ci compile

* Merged LoDTensor with Tensor,test=allcases

* Patched python level LoDTensor

* Patched python level LoDTensor

* Merge Tensor into DenseTensor

* Fixed namespace issues,test=allcases

* Fixed merge issues

* Fixed inference issues

* Fixed NPU test issues

* Fixed merge issues

* add pten::Place data structure.

* update ci problem

* fix ci problem

* update

* using platform::Place=pten::Place

* remove BOOST_GET_CONST for CPUPlace and GPUPlace

* compile pass 25%.

* compile pass 45%

* compile pass 60%

* remove boost_get for xpu npu mlu and ipu

* compile pass on cpu and gpu.

* fix compile problem

* fix compile error.

* update

* fix ci problem

* update

* ci approve

* fix ci problem

* fix ci eager test problem

* remove BOOST_GET_CONST

* fix npu compile

* change 'math' to 'math_kernel'

* fix compile bugs

* merge develop

* fix compile bugs

* fix compile bugs

LGTM