feat(utils): implement report-diff.md formatting for monorepos

[matejchalk]

Part of #731 (only Markdown formatting)

Scope

• Merged separate groups and audits details element into single details element to make the Markdown more compact. Applies to both standalone and monorepo comments.
• Implemented function to format array of project diffs as single comment.
  • Section per project with status summary.
  • Unchanged categories are omitted from table.
  • Unchanged projects only mentioned in footer.
  • Projects sorted from most changed.
• Extracted diff formatting utilities into separate file and unit tested them.

Next steps

• Implement CLI command to merge multiple report-diff.jsons into single report-diff.md.
• Use command in GitHub Action (https://github.com/code-pushup/github-action/issues/35)

[github-actions[bot]]

Code PushUp

🤨 Code PushUp report has both improvements and regressions – compared target commit a778eeac60181344b2036ea3daeb9f06c5006f42 with source commit da41f1873bd38b5cef4eac659b03747372b2aae9.

🕵️ See full comparison in Code PushUp portal 🔍

🏷️ Categories

🏷️ Category	⭐ Previous score	⭐ Current score	🔄 Score change
Performance	🟡 51	🟡 52
Code coverage	🟡 90	🟡 90
Custom checks	🟡 67	🟡 67	–
Security	🟢 100	🟢 100	–
Updates	🟡 78	🟡 78	–
Accessibility	🟢 91	🟢 91	–
Best Practices	🟢 100	🟢 100	–
SEO	🟡 61	🟡 61	–
Bug prevention	🟢 100	🟢 100	–
Code style	🟢 99	🟢 99	–

👍 2 groups improved, 👍 4 audits improved, 👎 3 audits regressed, 81 audits changed without impacting score

## 🗃️ Groups | 🔌 Plugin | 🗃️ Group | ⭐ Previous score | ⭐ Current score | 🔄 Score change | | :--------------------------------------------------------------------------- | :-------------------- | :--------------: | :-------------: | :--------------------------------------------------------------: | | Lighthouse | Performance | 🟡 51 | 🟡 **52** |  | | [Code coverage](https://www.npmjs.com/package/@code-pushup/coverage-plugin/) | Code coverage metrics | 🟡 90 | 🟡 **90** |  | 18 other groups are unchanged. ## 🛡️ Audits | 🔌 Plugin | 🛡️ Audit | 📏 Previous value | 📏 Current value | 🔄 Value change | | :--------------------------------------------------------------------------- | :--------------------------------------------------------------------------------------------------------------------------------- | :---------------------------------------------------------: | :-------------------------------------------------------------: | :--------------------------------------------------------------------------------: | | Lighthouse | Speed Index | 🟥 8.5 s | 🟥 **6.4 s** |  | | Lighthouse | Largest Contentful Paint | 🟨 3.1 s | 🟨 **3.4 s** |  | | Lighthouse | First Meaningful Paint | 🟨 2.8 s | 🟨 **2.8 s** |  | | Lighthouse | First Contentful Paint | 🟨 2.8 s | 🟨 **2.8 s** |  | | [Code coverage](https://www.npmjs.com/package/@code-pushup/coverage-plugin/) | Branch coverage | 🟨 84.4 % | 🟨 **84.9 %** |  | | [Code coverage](https://www.npmjs.com/package/@code-pushup/coverage-plugin/) | Line coverage | 🟩 91.6 % | 🟩 **91.8 %** |  | | [Code coverage](https://www.npmjs.com/package/@code-pushup/coverage-plugin/) | Function coverage | 🟩 92.1 % | 🟩 **92.3 %** |  | | Lighthouse | Minimizes main-thread work | 🟥 23.4 s | 🟥 **21.3 s** |  | | Lighthouse | Avoids enormous network payloads | 🟩 Total size was 1,806 KiB | 🟩 **Total size was 1,804 KiB** |  | | Lighthouse | Uses efficient cache policy on static assets | 🟨 28 resources found | 🟨 **27 resources found** |  | | Lighthouse | JavaScript execution time | 🟥 9.2 s | 🟥 **10.5 s** |  | | Lighthouse | Eliminate render-blocking resources | 🟥 Potential savings of 360 ms | 🟥 **Potential savings of 1,110 ms** |  | | Lighthouse | Max Potential First Input Delay | 🟥 2,810 ms | 🟥 **3,470 ms** |  | | Lighthouse | Total Blocking Time | 🟥 8,820 ms | 🟥 **8,240 ms** |  | | Lighthouse | Time to Interactive | 🟥 16.4 s | 🟥 **16.5 s** |  | | Lighthouse | Metrics | 🟩 16353 | 🟩 **100%** |  | | Lighthouse | Initial server response time was short | 🟩 Root document took 370 ms | 🟩 **Root document took 290 ms** |  | | Lighthouse | Network Round Trip Times | 🟩 10 ms | 🟩 **40 ms** |  | | Lighthouse | Server Backend Latencies | 🟩 120 ms | 🟩 **140 ms** |  | | Lighthouse | Avoids an excessive DOM size | 🟥 2,229 elements | 🟥 **2,222 elements** |  | | [JS Packages](https://docs.npmjs.com/) | [Outdated NPM prod dependencies.](https://classic.yarnpkg.com/docs/dependency-types#toc-dependencies) | 🟨 14 outdated package versions (4 major, 3 minor, 7 patch) | 🟨 **13 outdated package versions (4 major, 3 minor, 6 patch)** |  | | Lighthouse | Uses HTTPS | 🟩 0 | 🟩 **passed** |  | | Lighthouse | Has a `` tag with `width` or `initial-scale` | 🟩 0 | 🟩 **100%** |  | | Lighthouse | Screenshot Thumbnails | 🟩 0 | 🟩 **100%** |  | | Lighthouse | Final Screenshot | 🟩 0 | 🟩 **100%** |  | | Lighthouse | No browser errors logged to the console | 🟩 0 | 🟩 **passed** |  | | Lighthouse | Avoid chaining critical requests | 🟩 10 chains found | 🟩 **10 chains found** |  | | Lighthouse | Displays images with correct aspect ratio | 🟩 0 | 🟩 **passed** |  | | Lighthouse | Serves images with appropriate resolution | 🟩 0 | 🟩 **passed** |  | | Lighthouse | Avoids deprecated APIs | 🟩 0 | 🟩 **passed** |  | | Lighthouse | Avoids third-party cookies | 🟩 0 | 🟩 **passed** |  | | Lighthouse | Preconnect to required origins | 🟩 0 | 🟩 **100%** |  | | Lighthouse | All text remains visible during webfont loads | 🟩 0 | 🟩 **100%** |  | | Lighthouse | Diagnostics | 🟩 0 | 🟩 **100%** |  | | Lighthouse | Network Requests | 🟩 0 | 🟩 **100%** |  | | Lighthouse | Tasks | 🟩 0 | 🟩 **100%** |  | | Lighthouse | Resources Summary | 🟩 0 | 🟩 **100%** |  | | Lighthouse | Avoid long main-thread tasks | 🟩 20 long tasks found | 🟩 **20 long tasks found** |  | | Lighthouse | Page has valid source maps | 🟩 0 | 🟩 **passed** |  | | Lighthouse | Ensure CSP is effective against XSS attacks | 🟩 0 | 🟩 **100%** |  | | Lighthouse | Script Treemap Data | 🟩 0 | 🟩 **100%** |  | | Lighthouse | `[aria-*]` attributes match their roles | 🟩 0 | 🟩 **passed** |  | | Lighthouse | Values assigned to `role=""` are valid ARIA roles. | 🟩 0 | 🟩 **passed** |  | | Lighthouse | ARIA attributes are used as specified for the element's role | 🟩 0 | 🟩 **passed** |  | | Lighthouse | Deprecated ARIA roles were not used | 🟩 0 | 🟩 **passed** |  | | Lighthouse | `[aria-hidden="true"]` is not present on the document `` | 🟩 0 | 🟩 **passed** |  | | Lighthouse | `[aria-hidden="true"]` elements do not contain focusable descendents | 🟩 0 | 🟩 **passed** |  | | Lighthouse | `[role]`s have all required `[aria-*]` attributes | 🟩 0 | 🟩 **passed** |  | | Lighthouse | Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children. | 🟩 0 | 🟩 **passed** |  | | Lighthouse | `[role]` values are valid | 🟩 0 | 🟩 **passed** |  | | Lighthouse | ARIA `tooltip` elements have accessible names | 🟩 0 | 🟩 **passed** |  | | Lighthouse | `[aria-*]` attributes have valid values | 🟩 0 | 🟩 **passed** |  | | Lighthouse | `[aria-*]` attributes are valid and not misspelled | 🟩 0 | 🟩 **passed** |  | | Lighthouse | Buttons have an accessible name | 🟩 0 | 🟩 **passed** |  | | Lighthouse | Document has a `