refactor(react-16): migrate to new react version

[dubisdev]

We are migrating to react 16 (the goal is to migrate to the last React version).

DONE

• Refactored some class components to functional components (07b5cb1, 8dfc73c. b9a2f63)
• Removed preload and use useEffect (4f9669a)
• Update react-markdow

BROKEN (Already fixed)

• Some functionalities are broken due to the update. Once all components have been migrated to the new react version the logic will be easier to understand and they will be fixed.

Known issues:

• React virtualized is not updating the results list and it is empty some times.

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• Select settings are not showing the value (but it still works)

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  (search engine should appear but is missing)

Related PRs

We need to update related packages as cerebro-ui

• refactor(react-16): migrate to react 16 cerebro-ui#7

Breaking changes

• All related to migrate to React 16 (https://reactjs.org/blog/2017/09/26/react-v16.0.html)
• React-Select has been updated so some plugins using the "Select" settings might have UI problems that won't affect to the final product. See more:
• https://react-select.com/upgrade-to-v2
• https://react-select.com/upgrade#from-v2-to-v3

[dubisdev]

Hi @oguhpereira

As this is going to be a big PR, it would be nice if you could start reviewing now.

[ogustavo-pereira]

Everything working normally on linux

[dubisdev]

I fixed the error with Selecting settings. Seems like they changed the API and I didn't saw the change for value prop
https://react-select.com/upgrade-to-v2#simple-value

[dubisdev]

The error with react-virtualized is also fixed. I'll update some of the docs to make examples work with these breaking changes.