* move DataType from paddle::experimental to phi

* convert namespace

* convert namespace

* convert namespace

* clarify namespace

* convert more datatype

* Revert "convert more datatype"

This reverts commit 083b462959e6a22d4d8767707b628b95b396642e.

* convert more in auto_code_generator

* fix conflicts for XPU

* fix namespace conflicts

* fix errors

* Revert "fix errors"

This reverts commit f9d9958b54ee32141112274c8a5c3c381ab0f876.

* fix errors

* fix formatting

* move DeviceContextPool to phi

* add EmplaceExternalContextFunc

* update namespace

* update cmake

* fix bugs and create context_pool_impl.h

* replace platform::is_xxx_place

* fix bugs

* update generator

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* fix enforce usage

* Revert "fix enforce usage"

This reverts commit 5f521f08a69713cee506e64a00ec6d9fba709e27.

* fix bugs

* rm XPUDeviceContext and CustomDeviceContext

* fix bugs

* fix fix context init bug

* fix bugs after merge

* fix bugs

* fix name

* fix mutable_data

* update and fix bugs

* fix bugs

* update

* fix bugs

* fix name

* fix bugs

* merge

* fix bugs

* create context_pool in phi/backends

* create context_pool in phi/backends

* fix bugs

* fix xpu bugs

* fix rocm bugs

* fix bugs

* fix bugs

* fix bugs

* fix xpu bugs

* update

* update

* fix bugs

* fix bugs

* rename multi_tensor_adam to fused_adam

* fix some bugs

* fix CI coverage

* rename test_fused_adam.py

* fix some bug

* add test_fused_adam_op.py

* fix some bugs

* fix fused_adam_op.cc

* fix CI bugs

* fix CI bug

* fix CI bug

* add multi_tenosr_adam

* update multi_tensor_base.py, test_multi_tensor_adam.py, adamw.py

* fix adam.py optimizer.py

* fix adamw.py

* fix test_multi_tensor_adam.py

* fix CI bug

* fix CI coverage

* fix ci bug

* fix betapow

* fix some bugs

* fix test_adamw_op.py

* fix CI coverage

* fix multi_tensor_adam_kernel.cc

* fix CI bug

* fix multi_tensor_adam_op.cc and test_multi_tensor_adam.py

* fix code style

* update C++ parts

* remove python parts modification temporarily

* add C++ ut

* update betapow copy code logic

* fix ci ut

* fix windows ci

* fix coverage ci

* improve coverage rate

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Co-authored-by: Nsneaxiy <sneaxiy@126.com>