[BD-46] feat: replace of variables SCSS to CSS

[PKulkoRaccoonGang]

Description

• implement design tokens for primitive SCSS variables in each component
• refactor component SCSS styles to use new CSS variables with minimal breaking changes (use tokens/replace-variables.js script).

Merge Checklist

• If your update includes visual changes, have they been reviewed by a designer? Send them a link to the Netlify deploy preview, if applicable.
• Does your change adhere to the documented style conventions?
• Do any prop types have missing descriptions in the Props API tables in the documentation site (check deploy preview)?
• Were your changes tested using all available themes (see theme switcher in the header of the deploy preview, under the "Settings" icon)?
• Were your changes tested in the example app?
• Is there adequate test coverage for your changes?
• Consider whether this change needs to reviewed/QA'ed for accessibility (a11y). If so, please add wittjeff and adamstankiewicz as reviewers on this PR.

Post-merge Checklist

• Verify your changes were released to NPM at the expected version.
• If you'd like, share your contribution in #show-and-tell.
• 🎉 🙌 Celebrate! Thanks for your contribution.

[openedx-webhooks]

Thanks for the pull request, @PKulkoRaccoonGang!

When this pull request is ready, tag your edX technical lead.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (feat/design-tokens@1f0749d). Click here to learn what that means.
Patch has no changes to coverable lines.

Additional details and impacted files

@@                  Coverage Diff                  @@
##             feat/design-tokens    #1633   +/-   ##
=====================================================
  Coverage                      ?   91.57%           
=====================================================
  Files                         ?      208           
  Lines                         ?     3537           
  Branches                      ?      821           
=====================================================
  Hits                          ?     3239           
  Misses                        ?      283           
  Partials                      ?       15           

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[openedx-webhooks]

@PKulkoRaccoonGang 🎉 Your pull request was merged! Please take a moment to answer a two question survey so we can improve your experience in the future.