Update eslint and related dependencies

[daniel-wer]

This PR updates eslint and all related dependencies. See issue #2880 for related discussion. I waited till eslint-config-airbnb officially added support for eslint v5 and another issue in eslint-plugin-react was fixed. There is a remaining issue in babel-eslint (which doesn't look like it's going to be fixed soon, PR has been open for months), for which I've added eslint-ignores with a hint when to remove them.

URL of deployed dev instance (used for testing):

• https://updateeslint.webknossos.xyz

Steps to test:

• As a lot of setState calls were refactored I'll probably use the manual testing protocol, not sure yet.
• Thorough review ;)

Issues:

• fixes Update eslint to v5, and eslint related plugins #2880

---

• Updated changelog
• Updated migration guide if applicable
• Needs datastore update after deployment
• Ready for review

[daniel-wer]

I sorted the rules alphabetically, which is why there are so many changes. I've also added a couple of rules here. Easiest way to check (if you want to) is probably to sort the rules from the old file alphabetically and then do a diff :/

[philippotto]

Nice diligent work 👍 🎉