Since akg supports both Ascend and Gpu, but their supported type and format are different,
so we use two directory "ascend" and "gpu" to store their registers respectively, and use
an attribute "processor" to distinguish them.

Main changes:
1) Add two op register class "AkgAscendRegOp" and "AkgGpuRegOp", inherited from the original AkgRegOp.
2) Rewrite akg ascend op registers with new interface, move them into directory "ascend".
3) Rename the imply_type from "AutoDiff" to "AKG".
4) Modify function FindOp, check the processor when imply_type is "AKG".
5) Modify function CheckRepetition, remove the judgement for impl_path, check processor instead.

TODO: Remove op registers in akg root path.

Merge pull request !2867 from huanghui/vm-anf-ir-graph-pb-dump

Merge pull request !3052 from caifubi/data-dump

Merge pull request !2754 from laiyongqiang/mem_opt

Merge pull request !3047 from wangqiuliang/fix-ci-cpplint

Merge pull request !3035 from ZhangQinghua/master

Merge pull request !2963 from BowenK/python_pass_clean

Merge pull request !3043 from BowenK/master

update directory and delete some

add hub directory

Merge pull request !3042 from wangqiuliang/fix-sens-tensor-check-issue

Merge pull request !3025 from lichen/add_embedding_look_up_op

Merge pull request !3037 from linqingke/mass

Merge pull request !3040 from islam_amin/bounding_box_augment_bugs

Merge pull request !2970 from panbingao/master

Merge pull request !3041 from JesseKLee/pr2891_comments

Merge pull request !3009 from dessyang/master

Merge pull request !2891 from Jamie/CacheOp_dev

Merge pull request !3029 from jiangjinsheng/issue_fix4

Merge pull request !3031 from wangqiuliang/fix-tensor-bool-operation

Merge pull request !3004 from mxm/fix_codedex

Merge pull request !3027 from ZPaC/adaptation-for-ps-mode

Merge pull request !2992 from hewei/decouple_ir_others

Merge pull request !2981 from lianliguang/primitive-decoupling

Merge pull request !2807 from riemann_penn/apply_indexed_slices

1. delete useless code
2. add const to Parameter which not been changed
3. check return code when call safe function memcpy_s

Merge pull request !3026 from ZPaC/add-front-end-ps-optim-expression

Merge pull request !2791 from changzherui/subgraph

Merge pull request !3028 from wukesong/create_dataset_modify

Merge pull request !3013 from amongo/fix_tensor_bool_add_float

Merge pull request !2877 from wukesong/add_lenet_alexnet_readme