Upgrade storybook and its addons to v7

[flacial]

Problem

TypeScript won't get upgraded to v5 because of this bug with storybook. And all of storybook addons won't be upgraded to v7. They provided two solutions, a workaround and upgrading to v7.

Solution

• Follow this guide for upgrading storybook: https://github.com/storybookjs/storybook/blob/next/MIGRATION.md#from-version-65x-to-700
• Follow this guide for upgrading storybook/react: https://storybook.js.org/migration-guides/7.0

After this, you'll have to fix the breaking changes.

• Update our Vercel build step to use Node.js v16
• Upgrading webpack to v5

On second thought, I think the two links are the same.

[flacial]

Related to #2859

[flacial]

There are a few issues preventing the migration:

• The flag -s is working to define the static assets directory
• SCSS files are getting compiled as SASS
• Memory leak when running the storybook server with all the stories