* [python] Add task decorator for python function
* Add decorator `@task`
* Add a tutorial about it
* Change tutorial doc and combine into traditional docs
* Add sphinx-inline-tab for better view
* revert not need change
* Correct python function indent
* Correct integration test
* Make sure all file with `.py` extension and all file
end with "_example"
* Make sure all examples have `__doc__`
* Make sure not have duplicate process definition name
* Make sure process definition same as filename
close: #7729
Jiajie Zhong