Summary:
This PR is a follow up for the contributing content move on the website:
* https://github.com/facebook/react-native-website/pull/3120
It replaces most of the CONTRIBUTING file content with a reference to the contributing overview page on the website, which has been based off the content of this file.
Additionally I have searched thought the code for the wiki links and replaces theme with the correct website links. There was an instance where comment was referring to an old and removed a while ago wiki page, so I just get rid of this link.
## Changelog
[Internal] [Chore] - Update CONTRIBUTING.md, replace wiki links
Pull Request resolved: https://github.com/facebook/react-native/pull/34035
Test Plan: N/A
Reviewed By: lunaleaps
Differential Revision: D37318814
Pulled By: cortinico
fbshipit-source-id: d3f5e5c5bd477c0de5c4f0f1d5de81f464b9f5b4
Simek
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