* refine metric/evaluator doc

* resolve comments

* resolve comments

* Add Visualizer tutorials

* Add Visualizer designs

* update

* update

* update

* fix commit

* add demo image

* simplify code according to #440 and add some results picture

* replace image url

* update

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

* 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

* [Doc] Update runner documents.

* update

* fix link

* update

* update

* Update import manner of Runner

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