add paddle.nn.initializer API, including: Normal, TruncatedNormal, Uniform, XavierNormal, XavierUniform, Assign (#27769)

* test=develop, bug fix for parameter_recv
* test=develop, for unittest, test_fleet_rolemaker_new

*test=kunlun

* add multitask

* add multitask, test=develop

* fix code style, test=develop

* add partail push dense, test=develop

* fix has_kay in py3, test=develop

* fix, test=develop

* fix, test=develop

* fix, test=develop

* fix norm api doc, test=develop

* fix error message, test=develop

* fix api norm, test=develop

* add adagrad, test=develop

* fix bug, test=develop

* fix bug, test=develop

* add spetral_norm, test=develop

* fix adagrad, test=develop

* merge , test=develop

* add lookup_table_v2_op_xpu, test=kunlun

* add lookup_table_v2_op_xpu, test=kunlun

* change some Tips ,test=kunlun

* fix gpu version paddle Error when have no CUDA device

* optimize format and add new unittest

* fix coverage problem

* fix unittest format

* change static mode to dygraph mode

* use subprocess in unittest

Made a change in python API to support the GPU version of unique OP working in static graph (#27899)

* Made a change to support unique op working in static graph

* Correct python format error

Add api of KaimingUniform & KaimingNormal in paddle.nn.initializer

As the title

As the title

* add dropout,log_loss, test=kunlun
* fix dropout, test=kunlun
* polish error message, test=kunlun
* change boost::get to BOOST_GET_CONST, test=kunlun
* fix copyright, test=kunlun

* support mean,softmax_with_cross_entropy on Baidu Kunlun,test=kunlun

* fix unittests error,test=kunlun

* delete boost::get,test=kunlun

* add xpu sgd & momentum

* Fix en doc for rnn.py. test=document_fix

* add sumary feature

* refine printting tensor

* add sci_mode

* add sample code

* fix indent error

* fix _format_item

* polish code

* support item indent

* add ut

* set place for ut

* fix py2 issue

* fix ut

* add conv for xpu, test=kunlun

* polish error_message, test=kunlun

* polish error_message, test=kunlun

* fix copyrigth, test=kunlun

* add local_response_norm in nn.functional and nn.layer, test=develop

* update layers to functional api, test=develop

* fix ci coverage, test=develop

* fix unittests bug, test=develop

As the title

* add xpu slice op
test=xpu

* add slice xpu op
test=xpu

* code style
test=kunlun

* style
test=kunlun

* format
test=kunlun

* support gradient merge with recompute, test=develop
test=develop

*test=kunlun

* modify test_load_op save path from /tmp to ./, test=develop

* trigger kunlun ci, test=kunlun

* trigger kunlun ci, test=kunlun

* update index sample

* add gather_op xpu, test=develop, test=kunlun

* fix ut, test=develop, test=kunlun

* fix the ut,test=develop, test=kunlun

* polish save load en doc details, test=document_fix

* polish details, test=document_fix

* remove blank, test=document_fix

* fix ascii error, test=document_fix

* update fc's input to x, test=document_fix

* update fc argument activation, test=document_fix

* 1. remove paddle.unique_with_counts api, which counts as unique api
2. add paddle.math.increment(x, value=1.0, name=None) api
3. replace paddle.sums with paddle.add_n api
4. update paddle.metric.accuracy api (add name parameter)

* fix doc and unittest of 2.0 lr_scheduler

* fix doc of 2.0 lr_scheduler

* fix unittest

* fix english doc of lr_scheduler

* fix api name of lr scheduler

* fix api name of lr scheduler

Update code examples for api2.0 

* remove test_lac predictor run case

* refine fleetrun.ps_launch

* update fleet run for multi device support

* ps_graph support ps-gpu

* fix heter save

* add heter save unittest

* fix unittest & simple code

* update fleetrun

* fix fleetrun

* fix launch barrier

* fix role maker

* add paddlecloud rolemaker unittest

* rename heter_worker_device_guard