Consolidate eslint, stylelint and prettier config

[gfellerph]

It's possible to outsource and share stylelint config into it's own package/repo. Doing this would have the benefit that we could share that config between our packages and also other repos like the blueprint.

Sharing prettier config: https://prettier.io/docs/en/sharing-configurationshttps://prettier.io/docs/en/sharing-configurations
Stylelint config: https://stylelint.io/user-guide/get-started

Tasks

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1. Delete prettier configs from packages, keep only the one in the root
2. Create a shared config for stylelint and use it in the styles and other packages where we have sass/css files
3. Ensure eslint compatibility with prettier (format a file and then lint it, the file should have no linting errors)