chore(storybook): upgrade to storybook 7

[TobiasHeimGalindo]

Closes #955

Proposed Changes

upgrade storybook to latest (7.0.21) to fix the docPage copy bug (see here: storybookjs/storybook#18611 (comment))

Breaking Changes/ToDos:

• Migrate .stories.mdx files to MDX2:
  Completed the automated upgrade of the 64 .stories.mdx files from MDX1 to MDX2 format as prompted by Storybook. Please refer to the MDX2 section of the 7.0 migration guide for details.

• Upgrade to Storybook's 7 New Framework Format:
  Migrated the project to use Storybook's new framework: @storybook/web-components-webpack5. This involved:
  Removing the dependencies: @storybook/builder-webpack5 and @storybook/manager-webpack5.
  Adding the dependency: @storybook/web-components-webpack5.
  Updating the framework field in main.js to use @storybook/web-components-webpack5.
  Removing the core.builder field in main.js.
  More about this new framework format can be found here.

• Eslint Recommendations:
  In case we face any issues, we can always run the npx storybook@latest automigrate script to get the recommended ESLint configurations provided by Storybook.

[TobiasHeimGalindo]

Currently blocked by our current Node version, need to bump to v16

Storybook 7.0 requires Node 16 or above. If you are using an older version of Node, you will need to upgrade or keep using Storybook 6 in the meantime.