feat(article-footer): redesign footer + add feedback buttons

[caugner]

Summary

(MP-907)

Problem

We don't know how helpful our articles are.

Solution

Allow users to give feedback via a redesigned article footer.

Measurements:

Click source	Explanation
thumbs: article_footer -> 0	User clicked on "Yes"
thumbs: article_footer -> 1	User clicked on "No"
article_footer: feedback -> outdated	User submitted "Content is out of date"
article_footer: feedback -> incomplete	User submitted "Missing information"
article_footer: feedback -> code_examples	User submitted "Code examples not working as expected"
article_footer: feedback -> other	User submitted "Other"

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Screenshots

Theme	Before	After
Light
Dark

Feedback

Action	Light	Dark
Hover over "Yes" button
Hover over "No" button
After click on "No" button
After click on "Yes" button / After submit feedback form

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How did you test this change?

Ran yarn dev and opened http://localhost:3000/en-US/docs/Web#developer_tools_documentation locally.

Enabled REACT_APP_GLEAN_DEBUG=true and REACT_APP_GLEAN_ENABLED=true temporarily and checked that all events are properly measured via https://debug-ping-preview.firebaseapp.com/pings/mdn-dev.

[argl]

Tested locally, looks good to me.

[yin1999]

Hey @caugner. It would be nice if the "Learn how to contribute" link in translated documentations could be https://github.com/mdn/translated-content/blob/main/CONTRIBUTING.md