Add contributing section to the website

[existentialism]

From discussion in slack:

• List beginner-friendly and help wanted tagged issues (ex: https://hapijs.com/contribute), we might need to do a round of issue tagging/cleanup first.

• At the minimum link to CONTRIBUTING.md, but we probably want to integrate it?

• Link to resources like babel-handbook, AST explorer, etc.

[hzoo]

My thoughts was to do what reactjs.org has: create a few articles and then link to it from CONTRIBUTING.md but either works. https://facebook.github.io/react/contributing/how-to-contribute.html

https://github.com/kubernetes/kubernetes/tree/master/docs has a lot

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity 😴. It will be closed if no further activity occurs. Thank you for your contributions 👌!

[imbhargav5]

I would like to take this up!

[hzoo]

@imbhargav5 awesome, looks like there is already a PR in progress but stale now https://github.com/babel/website/pull/1126

[imbhargav5]

@hzoo So what do you think I should do? Should I wait for more activity or should I start afresh ? Or do you think there is a better way?

[koolamusic]

Is this still a concern, can it be taken up now babel has moved to docusaurus