Speed up start of the styleguidist

[dnlkoch]

Description

After fiddling around with the current configuration, it looks like the react-docgen-typescript is slowing down the initial build of the styleguidist tremendously while checking the props/types of any parent component (e.g. the extended antd types).

This suggests to skip this check in development mode which will result in decent startup times (before: ~180s. after: ~20 s), BUT the list of props might not be complete. There seems to be a bug while detecting the props of function components as well, see here.

Related issues or pull requests

#1375.

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Dependency updates
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe)
• I am unsure (we'll look into it together)

Do you introduce a breaking change?

• Yes
• No
• I am unsure (no worries, we'll find out)

Checklist

• I understand and agree that the changes in this PR will be licensed under the BSD 2-Clause License
• I have followed the guidelines for contributing
• The proposed change fits to the content of the code of conduct
• I have added or updated tests and documentation, and the test suite passes (run npm test locally)
• I'm lost; why do I have to check so many boxes? Please help!

[KaiVolland]

Two more big issue with styleguidist detected by your work. We should really investigate if we can replace it with something similar.

The PR is a good option anyway as it just changes the dev setup if im right. Feel free to merge.

[dnlkoch]

Yes, I agree, we should definitely check for an alternative.