Web performance optimizations

[plesiecki]

Hello World 👋

I would like to introduce some performance improvements for turnilo's frontend.
Optimizations list appears as follows:

• Extract CSS copyright comments from JS bundle. About 2Mb of dead code. Extract CSS from JS bundle #851
• Move polyfills to its own bundle. Embed as nomodule script. Polyfills bundle #854
• Split bundle into smaller chunks, e.g. extract Sentry code, DnD polyfill.
  • Dnd polyfill chunk #871
• Build and serve ES5/ES6. Build two client bundles — ES5 and ES6 #855
• Remove dead code from modules like highlight.js or moment.
  • Moment's dead code elimination #864
• Review dependencies and its imports. E.g. changing react-syntax-highligher import to react-syntax-highligher/src outputs smaller bundle.
  • Bump react-syntax-highlighter to save on bundle size #858
• Review bundle analyzer report and apply appropriate optimizations.
• Reduce dependencies usage, utilize smaller modules and modern API like fetch, URL, URLSearchParams .
  • Markdown parser lib change, snarkdown instead of marked. Build tests with babel instead of ts-node. #873
• Consider dynamic imports for better initial JS coverage.
  • Split visualizations into chunks #875
• Embed SVGs as images (url) instead of bundling these into JS bundle.
• Cache-Control for JS, CSS, SVG.
• CI Improvements:
  • Size limit action #862
  • Bundle analysis with Statoscope #861
  • Monitor bundle size with size-limit #860
  • Minor CI improvements #863