docs: create Docusaurus v2.1.0 release docs + changelog + release blog post

[slorber]

Motivation

Add 2.1.0 docs version + backport all docs changes from commits backported for the 2.1 release ( #8033)

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Note this looks like a hacky but possible good way to automate that docs backport process:

# Inspired by https://stackoverflow.com/a/63745988/82609

git format-patch -k --stdout v2.0.1...slorber/docusaurus-v2.1-backport -- website/docs | sed 's,a/website/docs,a/website/versioned_docs/version-2.1.0,g ; s,b/website/docs,b/website/versioned_docs/version-2.1.0,g' | git am -3 -k

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Preview links:

• https://deploy-preview-8036--docusaurus-2.netlify.app/blog/2022/09/01/docusaurus-2.1
• https://deploy-preview-8036--docusaurus-2.netlify.app/changelog/2.1.0/
• https://deploy-preview-8036--docusaurus-2.netlify.app/docs/2.1.0/

[netlify]

✅ [V2]

Name	Link
🔨 Latest commit	a6b8e72
🔍 Latest deploy log	https://app.netlify.com/sites/docusaurus-2/deploys/6310bf73b6bf750008734c40
😎 Deploy Preview	https://deploy-preview-8036--docusaurus-2.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

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[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	PWA	Report
/	🔴 46	🟢 98	🟢 100	🟢 100	🟠 80	Report
/docs/installation	🟠 78	🟢 100	🟢 100	🟢 100	🟢 90	Report

[netlify]

✅ [V2]

Name	Link
🔨 Latest commit	8a1d0d6
🔍 Latest deploy log	https://app.netlify.com/sites/docusaurus-2/deploys/6310d66ec1584500088074ed
😎 Deploy Preview	https://deploy-preview-8036--docusaurus-2.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site settings.

[github-actions]

Size Change: -1.64 kB (0%)

Total Size: 813 kB

Filename	Size	Change
website/.docusaurus/globalData.json	52.1 kB	-430 B (-1%)
website/build/assets/js/main.********.js	609 kB	-1.2 kB (0%)

ℹ️ View Unchanged

Filename	Size	Change
website/build/assets/css/styles.********.css	111 kB	0 B
website/build/index.html	40.8 kB	-16 B (0%)

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