WIP: Upgrade eslint (and everything)

[shadowspawn]

Pull Request

I keep going to update eslint, and then finding there are some transitive dependencies of standard that have still have not been updated to officially support eslint@7. I'm opening a PR so I don't do the work again! The linting is working ok but get a couple of warnings on install:

npm WARN eslint-plugin-import@2.18.2 requires a peer of eslint@2.x - 6.x but none is installed. You must install peer dependencies yourself.
npm WARN eslint-plugin-react@7.14.3 requires a peer of eslint@^3.0.0 || ^4.0.0 || ^5.0.0 || ^6.0.0 but none is installed. You must install peer dependencies yourself.

The eslint issue about the dependencies is: standard/standard#1518