* [Fix] resume std and mean

* refine docstring

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>

* fix ema load_state_dict

* fix ema load_state_dict

* fix for test

* fix by review

* fix resume and keys

* [Fix] Fix EMAHook trigger train loop init during testing.

* fix sync buffer

* update ut

* fix sync buffer

* fix sync buffer

* Move the design of hook to design/hook.md

* add relative links in docs

* update docstring of hooks

* refine checkpointhook docs

* refine

* fix comments

* refine

* add logging.md link in hook.md

* resolve comments

* fix typo

* BaseAveragedModel support load ckpt without module prefix

* refine docstring

* allow EMAHook does not load ckpt strictly

* add unit test for strict argument of EMAHook

* sync remote

* sync remote

* clean the code

* ema hook supports setting start iter

* fix unit test

* fix as comment

* fix as comment

* describe kwargs

* Fix ema hook and add unit test

* save state_dict of ema.module

save state_dict of ema.module

* replace warning.warn with MMLogger.warn

* fix as comment

* fix bug

* fix bug

* [Fix] Fix ema state dict swapping in EMAHook.

* fix pt1.5 ut

* add more comments

* [Enhance] Add RuntimeInfoHook to update runtime information.

* move lr to runtime info

* docstring

* resolve comments

* update ut and doc

* [Feature] Support EMA and SWA.

* add ema hook

* add avg model ut

* add more unit tests

* resolve comments

* fix warmup ema

* rename

* fix comments

* add assert

* fix typehint

* add comments