* [cherry-pick][Unstructured_prune] add local_sparsity (#916)

* [cherry-pick][unstructured_pruner] add local_sparsity args in demo (#920)

* [Unstructured_prune] add local_sparsity demo

* optimize unstructured pruner using GMP

* add uniittests for GMP pruner

* add training scripts for fleet and gmp; add conv1x1 pruning

* add conv1x1 pruning to dygraph

* unify hyper parameters across methods and scripts, static graph

* unify hyper parameters across methods and scripts, dynamic graph

* refine test cases

* fix singlecard training in static graph

* refine readmes

* update unstructured pruner api doc static

* update api docs dygraph

* fix bugs in api docs

* rename UnstructuredPrunerGMP to GMPUnstructuredPruner

* fix some format issues

* remove redundant methods/arguments

* description for gmp configs

* fix minor bugs

* fix test cases accordingly
Co-authored-by: Nwhs <wanghaoshuang@baidu.com>

* fix prune doc

* fix prune demo batchsize

* fix lr (#593)

* fix lr schedule in prune demo (#595)

* fix prune demo batchsize

* fix lr shcedule in prune demo
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Co-authored-by: Nwanghaoshuang <wanghaoshuang@baidu.com>

* remove softmax from demo/models (#596)

* fix prune demo batchsize

* fix lr shcedule in prune demo
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* remove softmax from demo/models
Co-authored-by: Nwanghaoshuang <wanghaoshuang@baidu.com>

* fix prune demo log
Co-authored-by: Nwanghaoshuang <wanghaoshuang@baidu.com>

* fix prune doc

* fix prune demo batchsize
Co-authored-by: Nceci3 <ceci3@users.noreply.github.com>

* fix prune demo

* migrage static api

* fix a bug

* fix dataloader

* remove sensitive_pruner module

* migrate prune module

* fix some bug for migrating the prune module to 2.0-rc

* update some 1.8 api

* change num_worker from 16 to 1

* migrate common and core module

* fix a api in rl controller

* fix dataloader

* remove sensitive_pruner module

* migrate prune module

* Make unitest support for Paddle2.0 API.

* Fix demo in static mode

* Remove unused lines

* Fix demo of darts

* add slim pruning implementation and related unitest test=develop