* Move train_cfg/test_cfg into model

* fixed fsaf

* fixed missing

* Add markdown lint in pre-commit hook

* add markdown lint

* fixed typos

* replace url with download

* update to http

* update FSAF model zoo

* Add foreground_dominate argument to center region assigner

* Add upsample_cfg support in FPN

* small fix

* Add multiple extra conv sources

* small logical fix

* Add neck tests for fpn

* Add neck tests for fpn

* fixed several typos

* resolved issues

* Removed extra_convs_source option

* added necks to apis.rst

* change according to comments

* add bbox_fields to expand and min iou crop

* reconfigured configs

* small fix

* added test for random crop and min iou random crop

* small change

* added valid_inds for masks in random crop according to #2802

* added config unit test

* deleted nas fpn config test

* revise according to comments

* add img_fields check in transform.py and test_transform.py

* Added notes for random crop and min iou random crop

* Added notes for random crop and min iou random crop

* Add bbox2label and bbox2mask key correspondence

* Update nas-fpn model
Add fsaf log

* starting to merge fsaf

* changed configs

* changed bbox_coder

* get_targets fun in AnchorHead class is modified to enable additional returns from _get_target_single

* effective area assigner and tblr bbox_coder are implemented

* added fsaf_head and config

* added more fsaf configs

* fixed the nan bbox_loss by clamping bbox_pred with min=1e-4

* fixed the nan bbox_loss by clamping bbox_pred with min=1e-4

* changed config

* formatter

* changed docstring

* Added ignored pixel-class pair for FSAF

* More elegant assignment for overlapping objects

* more documents in effective area assigner

* fixed a bug in object overlay

* Added no gt_bboxes case and pytest for assigner

* Added no gt_bboxes case and pytest for assigner

* changed default config

* fixed small bugs in FSAF head doc example

* resolved pr review comments.
1. Formats of comments and docstrings are modified
2. Obsolete arguments are removed from FSAFHead
3. AssignResults class is revised to be more compatible with old version

* Added more comments to FSAFHead

* resolved pr review comments

* resolved pr review comments
1. More flexible CenterRegionAssigner bbox priority
2. More flexible tblr_coder by adding normalize_by_wh flag
3. README modifications with model link
4. More docstrings and comments
5. Reformatted
6. Change of default normalizer in TBLRBBoxCoder from 1.0 to 4.0

* Corrected FSAF model path in readme

* Fixed the bug of bbox weights in fsaf head

Co-authored-by: wangxinjiang <wangxinjiang@sensetime.com>