Improve bundle doc for the `import` logic

Is your feature request related to a problem? Please describe. Thanks for @diazandr3s 's feedback, it’s not clear in the bundle doc that:

1. Which class names can be used in _target_ directly, which class should provide the full module path? answer: MONAI classes and functions can be used directly.
2. When using import in the config, which packages are pre-imported? seems monai, np, torch. answer: yes, the default behavior of ConfigParser will import monai, numpy, np, torch as these are MONAI min deps.
3. Should I import the components in the config? Like transforms, network, etc. answer: only need to import 3rd libs for expressions, not for _target_ instantiation.

Would be nice to enhance the bundle doc for these points.

[diazandr3s]

I missed this part of the question:

What do you guys feel when you started to develop a bundle? Do you want to refer to the documentation page or tutorial notebook?

I’d suggest having that in the Notebook format

I’ve created the DeepEdit bundle based on the already developed bundle for Spleen segmentation and the Notebook mostly. The development is easier when you have a JSON parser (i.e. online)

[Nic-Ma]

Hi @wyli ,

I think maybe we should provide the page for all the details of syntax with examples, then users just search this page for any syntax questions. Refer to the omegaconf: https://omegaconf.readthedocs.io/en/2.1_branch/usage.html#creating Many examples of bundle syntax can be found in this slides: https://docs.google.com/presentation/d/1qXl5-GT14kST68RDCJ408ilMpiHDCAN1QnecuRoqyZI/edit?usp=sharing

The tutorial notebook is just one practice example which can’t cover all cases.

Anyway, I am open for the discussion. @ericspod @diazandr3s What do you guys feel when you started to develop a bundle? Do you want to refer to the documentation page or tutorial notebook?

Thanks.