add instaboost in coco.py (#1739)

* add instaboost in coco.py

* Revert "add instaboost in coco.py"

This reverts commit 51af81ef88991782d54750761ef2dd394c7a38a8.

* add instaboost in data pipeline

* code format

* Update requirements.txt

* add README.md

* bug fix

* add link

* Update README.md

* install instaboost when necessary, keep r50 cfgs only

* ready to merge

* fix typo

* pass yapf

* minor formats

Co-authored-by: Wenwei Zhang <40779233+ZwwWayne@users.noreply.github.com>
Co-authored-by: Kai Chen <chenkaidev@gmail.com>