Replace extension drop-downs with toggles

[chrismwendt]

• Toggles instead of dropdowns + buttons
• Hover on the toggle to see where the extension is enabled/disabled
• Still asks for confirmation when enabling an extension that doesn't exist in the settings
• Pulls in @ijsnow's new and improved toggle ✨

[codecov]

Codecov Report

Merging #56 into master will increase coverage by 1%.
The diff coverage is 1.69%.

@@           Coverage Diff           @@
##           master      #56   +/-   ##
=======================================
+ Coverage   15.92%   16.93%   +1%     
=======================================
  Files          36       35    -1     
  Lines        1124     1063   -61     
  Branches      287      274   -13     
=======================================
+ Hits          179      180    +1     
+ Misses        945      883   -62

Impacted Files	Coverage Δ
src/extensions/manager/ExtensionCard.tsx	0% <ø> (ø)	⬆️
src/ui/generic/Toggle.tsx	0% <0%> (ø)	⬆️
src/extensions/ExtensionToggle.tsx	0% <0%> (ø)
src/settings.ts	60.6% <11.11%> (-7.82%)	⬇️

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[chrismwendt]

I don't feel that the lack of client-side prediction is too janky, and I don't want to risk introducing any bugs at the moment, so I'm merging this as-is.

[sourcegraph-bot]

🎉 This PR is included in version 10.0.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀