[Beta] Playing around with Stitches as a replacement for Emotion lib

[Vadorequest]

See #324 (comment)

See https://stitches.dev/docs/installation

Issues:

• Don't know how to replace Emotion ThemeProvider using Stitches.
  • ⚠️ Blocking, because part of our theme is dynamic and cannot be defined statically. Examples and best practices would be great.
  • Not sure if that's actually blocking since we use "preload", it should "just work", theoretically.
  • Possible to use https://github.com/callstack/react-theme-provider as an alternative
• ⚠️ The @stitches/react lib is currently in beta

[github-actions]

✅  Deployment SUCCESS
Commit 7fe6375 successfully deployed Next.js app 🚀 to https://nrn-v2-mst-aptd-at-lcz-sty-c1-elbsxmoqr-unly-oss.vercel.app
Deployment aliases (2): nrn-v2-mst-aptd-at-lcz-sty-c1-preview.vercel.app, nrn-v2-mst-aptd-at-lcz-sty-c1-css-stitches.vercel.app

[github-actions]

✅  Deployment SUCCESS
Commit 7fe6375 successfully deployed Storybook static site 📖 to https://nrn-v2-mst-aptd-at-lcz-sty-storybook-egil4t0eg-unly-oss.vercel.app
Deployment aliases (1): nrn-v2-mst-aptd-at-lcz-sty-storybook.vercel.app

[github-actions]

✅  E2E tests SUCCESS for commit 7fe6375 previously deployed at https://nrn-v2-mst-aptd-at-lcz-sty-c1-elbsxmoqr-unly-oss.vercel.app

[github-actions]

✅  E2E tests SUCCESS for commit 7fe6375 previously deployed Storybook static site at https://nrn-v2-mst-aptd-at-lcz-sty-storybook-egil4t0eg-unly-oss.vercel.app