feat(plugin-doc-coverage): add doc-coverage-plugin to analyze documentation in ts/js projects

[aramirezj]

This PR includes:

• documentation
• unit/integration tests
• usage of the plugin in the repository

E2e test will be in a followup PR

Closes #900

[github-actions]

Code PushUp

🤨 Code PushUp report has both improvements and regressions – compared target commit c219602 with source commit c219602.

🏷️ Categories

🏷️ Category	⭐ Previous score	⭐ Current score	🔄 Score change
Performance	🔴 49	🔴 49
Code coverage	🟢 91	🟢 91	–
Security	🟡 81	🟡 81	–
Updates	🟡 80	🟡 80	–
Accessibility	🟢 91	🟢 91	–
Best Practices	🟢 100	🟢 100	–
SEO	🟡 61	🟡 61	–
Bug prevention	🟢 100	🟢 100	–
Code style	🟢 100	🟢 100	–

👍 1 group improved, 👍 2 audits improved, 👎 3 audits regressed, 10 audits changed without impacting score

🗃️ Groups

🔌 Plugin	🗃️ Group	⭐ Previous score	⭐ Current score	🔄 Score change
Lighthouse	Performance	🔴 49	🔴 49

16 other groups are unchanged.

🛡️ Audits

🔌 Plugin	🛡️ Audit	📏 Previous value	📏 Current value	🔄 Value change
Lighthouse	Speed Index	🟥 6.0 s	🟥 6.7 s
Lighthouse	Largest Contentful Paint	🟨 3.8 s	🟨 3.6 s
Lighthouse	First Contentful Paint	🟨 2.9 s	🟨 2.9 s
Lighthouse	Time to Interactive	🟥 13.5 s	🟥 14.5 s
Lighthouse	Total Blocking Time	🟥 3,290 ms	🟥 4,840 ms
Lighthouse	Minimizes main-thread work	🟥 13.3 s	🟥 16.4 s
Lighthouse	JavaScript execution time	🟥 5.8 s	🟥 7.4 s
Lighthouse	Metrics	🟩 100%	🟩 100%
Lighthouse	Max Potential First Input Delay	🟥 2,540 ms	🟥 2,020 ms
Lighthouse	Avoids enormous network payloads	🟩 Total size was 1,820 KiB	🟩 Total size was 1,820 KiB
Lighthouse	Server Backend Latencies	🟩 350 ms	🟩 160 ms
Lighthouse	Uses efficient cache policy on static assets	🟨 28 resources found	🟨 28 resources found
Lighthouse	Initial server response time was short	🟩 Root document took 460 ms	🟩 Root document took 420 ms
Lighthouse	Eliminate render-blocking resources	🟥 Potential savings of 800 ms	🟥 Potential savings of 770 ms
Lighthouse	Network Round Trip Times	🟩 80 ms	🟩 70 ms

573 other audits are unchanged.

[BioPhoton]

Really good polished tests! 🧪
I made some suggestions to improve naming and other small things.

[BioPhoton]

Thanks for adding the tests.

Last thing I found was a outdated readme. After that we are good to go.

[BioPhoton]

WONDERFUL!

cc @vmasek and @matejchalk