add new config sample and check scripts (#2216)

* add new config sample and check scripts

* context managere to prevent import

* refactor backbone, add caffe

* add fast rcnn

* all basci config done

* rm coco_proposal

* add scratch, wider_face, voc

* add reppoints

* delete device id, auto resume

* add libra_rcnn, ms_rcnn, nas_fpn

* add hrnet, fcos

* add free_anchor, gn, grid_rcnn, guided_anchoring, gcnet, ghm, gn+ws

* finished all, but some need refactor and unified logic

* fixed albu

* update ReseNet101

* reduce ResNet101, add norm_cfg, 4conv1fc

* refactor caffe backbone

* merge act_cfg, dcn from master

* rename 2fc head, add 4conv1fc head

* delete 4con1fc model

* rename components -> _base_

* flatten _base_

* refactor _base_ structure

* refactor config structure

* reduce _base/models

* rename all config

* add _coco inside configs

* fixed _coco in files

* fixed albu in test

* migrate to new sys

* fixed test

* fixed test

* rm cascade, fast_rcnn

* rm cascade, fast_rcnn from _base_

* fixed fcos_center

* rename from rule

* collopse third party model

* fixed test

* fixed some minor bug

* rename gn-neck_head -> gn-neck+head