Not recommended: require-fetch-import

I see that there is a [plan to add require-fetch-import to the recommended rule set](https://github.com/ember-cli/eslint-plugin-ember/issues/1169).

I don't think this is a good idea. It pushes people toward a pattern that we are already trying to kill: importing from paths that aren't real packages.

At a minimum, I don't think we should enable this by default until https://github.com/ember-cli/ember-fetch/issues/330 is addressed.

Personally, I don't think it's appropriate to require people to import `fetch` at all. It's a web standard, linting against it in people's code is contrary to our efforts to bring ember into better alignment with javascript-ecosystem-wide standards, and the global `fetch` is equally easy to patch/polyfill in all environments (like tests and fastboot) where it's helpful to do that.