remove the AdamOptimizer、SGDOptimizer、MomentumOptimizer、ModelAverage、LookaheadOptimizer、FtrlOptimizer、DecayedAdagradOptimizer、DpsgdOptimizer in fluid and relocate the ExponentialMovingAverage、PipelineOptimizer、GradientMergeOptimizer and change optimizer base for LarsMomentumOptimizer and RecomputeOptimizer (#55970)

* change the optimizer base for SGDOptimizer

* change the optimizer base for SGDOptimizer

* replace the SGDOptimizer with SGD

* fix bug of sgd

* change the optimizer base for MomentumOptimizer

* fix the remaining tests

* remove the Momentum in fluid/optimizer.py

* fix bug

* fix bug

* fix bug

* fix bug

* Update test_resnet_cinn.py

* Update test_resnet_prim_cinn.py

* fix bug

* fix bug

* fix bug

* remove the ModelAverage in fluid

* remove the LookaheadOptimizer in fluid

* fix bug

* remove AdamOptimizer in fluid

* Update test_image_classification_fp16.py

* fix bug

* relocate the ExponentialMovingAverage in fluid

* restore the static api

* remove the FtrlOptimizer in fluid

* remove the DecayedAdagradOptimizer in fluid

* remove the DpsgdOptimizer in fluid

* fix bug

* fix codestyle

* fix bug

* fix bug

* relocate the PipelineOptimizer

* relocate the GradientMergeOptimizer

* fix bug

* fix bug

* fix bug

* fix doc

* Update __init__.py

* Update test_fleet_qat_meta_optimizer.py

* change optimizer base for LarsMomentumOptimizer

* fix bug

* fix conflict

* fix code-style

* fix sample codes

* fix bug

* fix bug

* fix cinn bug

* fix bug

* fix bug

* Update qat_optimizer.py

* Update __init__.py

* fix bug

* change optimizer base for RecomputeOptimizer

* fix bug

* fix bug

* Update test_imperative_optimizer_v2.py

* mv all unittests test

* fix error

* fix error

* fix

* fix

* del unittests

* fix paddle_build.sh

* fix

* fix test

* fix add test

* fix

* fix

* fix

* merge develop

* fix

* fix

* fix

* fix

* fix

* merge develop

* fix test_async_read_write

* fix test_async_read_write

* merge develop

* fix

* fix import legacy_test

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* fix bug

* fix

* fix coverage test bug

* fix

* fix

* fix

* fix

* fix

* fix code sstyle

* fix code

* fix code

* fix

* fix

* fix

* del test_sequence_enumerate_op.py

* fix

* rm retain grads flag for tests

* modify fill_diagonal

* retain grads for fill_diagonal tests

* reset sum & concat

* fix fill_diagonal

* rm unittests eager guard tests imperative_save2using

* minor change

* rm legacy test

* rm eager test

* [remove fluid] fluid dygraph Embedding

* [remove fluid] fluid dygraph Embedding

* [remove fluid] fluid dygraph Embedding

* [remove fluid] fluid dygraph Embedding

* [remove fluid] fluid dygraph Embedding

* [remove fluid] fluid dygraph Embedding

* isort all files

* revert conflicting files

* revert conflicting files

* revert conflicting files

* revert conflicting files

* revert conflicting files

* [CodeStyle][py2][U008] remove unnecessary args in `super()`

* remove remained args

* revert changes in test_pylayer_op

* Revert "revert changes in test_pylayer_op"

This reverts commit ff185a9ae738afac3b0264f61bde6c6b7f72e7c4.

* revert some changes in example code

* [CodeStyle][E711] use `is`/`is not` for comparison with `None`

* `self.assertTrue($A is None)` -> `self.assertIsNone($A)`

* `self.assertTrue($A is not None)` -> `self.assertIsNotNone($A)`

* `self.assertFalse($A is None)` -> `self.assertIsNotNone($A)`

* `self.assertEqual($A, None)` -> `self.assertIsNone($A)`

* `self.assertNotEqual($A, None)` -> `self.assertIsNotNone($A)`

* update config

* re-blacken python code

* temporarily disable date and diff_py_file

* skip a format

* [CodeStyle] remove all future import

* revert test_error.py

* restore future import in example code

* use yapf to format all python file

* yapf exclude two unittests file for they rely on writing and reading file, and format will break them

* disable diff_py_file because too many diff files cause command following failed

* [Eager] FLAGS_retain_grad set false

* Add FLAGS_retain_grad_ for some tests

* Add FLAGS_retain_grad_ to some tests

* modified set_flags

* modified set_flags

* fix windows-ci and windows-openblas-ci

* import paddle.fluid

* [Eager] Support SelectedRows in eager mode

* Remove unnecessary codes

* Adapt new dygraph flag

* update the demo code and the doc of varbase.backward.

* update the doc of the fake interface `paddle.fluid.Variable`.

* remove BackwardStrategy.

* Directory migration, test=develop

* Change imperative from paddle init to paddle framework, test=develop

* Fixed jit bug, test=develop

* default static mode, test=develop

* fixed format and create parameter belongs to framework, test=develop

* Fixed import package, test=develop

* fix __init__ format, test=develop

* fixed alias problem

* fixed paddle.enable_imperative problems, test=develop

* Add unittest

* delete install_check comment

* Fixed unittest timeout

* fixed unittest error

* move Program default_xx_program to static package

* optimize unittest method

* fixed framework __init__ format

* fixed jit path

* delete alias

* move jit to paddle

* Fixed unittest format

* fixed paddle.default_main_program

* Fixed save load API in paddle __init__.py

* fixed ci paddle.imperative.to_variable

* copy dygraph api to paddle.imperative, test=develop

* polish the code, test=develop

* polish code, test=develop

* polish code, test=develop

* move paddle.imperative.Layer to paddle.nn.Layer, test=develop

* refine grad maker, test=develop

* refactor tracer stage 1, test=develop

* merge develop to solve conflict third times, test=develop

* move private weight properties to public ones
test=develop

* revert changes to FC
test=develop

* fix unittest
test=develop

* fix unittest
test=develop

* fix coverage
test=develop

* fix merged dev
test=develop

* bug fix
test=develop

* remove params in Tracer object, test=develop

* Repair failed optest, test=develop

* remove build_once & name_scope (Conv2D)
test=develop

* fix unittest
test=develop

* Conv2DTranspose

* Conv3D & Conv3DTranspose
test=develop

* Pool2D & BatchNorm

* Embedding

* LayerNorm

* GRUUnit & NCE

* PRelu

* BilinearTensorProduct

* GroupNorm & SpectralNorm

* TreeConv
test=develop

* fix LayerNorm in transformer unnittest
test=develop

* disable LayerNorm or BatchNorm in multicard
test=develop

* refine Layer.create_parameter api
test=develop

* refine LayerNorm, remove begin_norm_axis param, add normed shape check
test=develop

* LayerNorm bug fix
test=develop

* fix optest,test=develop

* fix optest, test=develop

* fix optest for pass parameter_list when constructing an Optimizer class instance, test=develop

* polish code for better code style, test=develop

* fix se_resnext optest, test=develop

* polish code for better code style, test=develop
Co-authored-by: Nsongyouwei <youwei0314@gmail.com>

test=develop

* support SelectedRows in dygraph, test=develop

* fix bug of _grad_ivar interface, test=develop

* add optest for support seletedrows, test=develop

* fix bug for gradient_accumulator in GPU mode, test=develop

* fix error when Selectedrows addto LodTensor in sorted_gradient mdoe in dygraph, test=develop

* refine and simplify gradient accumulator code, test=develop

* add optest, test=develop

* add optest and simplify code, test=develop

* fix bug for test_imperative_selected_rows, test=develop

* add optest for Coverage, test=develop

* fix gradient interface and simplify code, test=develop

* update api for gradient, test=develop

* fix ShareDim's bug in DygraphExecutionContext class, test=develop

* add optest, test=develop