Remove stats tracking code

[nylen]

• Convert EnableTrackingPrompt tests to use shallow rendering - Add opt-in usage tracking for blocks added to post content #2140 (comment)
• Restructure bumpStat calls inside components: dispatch a Redux action, and bump the stat as a refx effect
• Improve the click-outside setup for the EnableTrackingPrompt popover
• Abstract the click-to-show Popover logic into a separate component (InlineHelpPopover)

[nylen]

Convert EnableTrackingPrompt tests to use shallow rendering

As noted at #2140 (comment), this isn't working for me for all of the tests.

[codecov]

Codecov Report

Merging #2278 into master will increase coverage by 2.65%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #2278      +/-   ##
==========================================
+ Coverage   24.96%   27.61%   +2.65%     
==========================================
  Files         151      151              
  Lines        4679     5396     +717     
  Branches      795      961     +166     
==========================================
+ Hits         1168     1490     +322     
- Misses       2965     3277     +312     
- Partials      546      629      +83

Impacted Files	Coverage Δ
blocks/api/parser.js	98.66% <ø> (-1.34%)	⬇️
editor/index.js	0% <ø> (ø)	⬆️
editor/inserter/index.js	0% <0%> (ø)	⬆️
editor/modes/visual-editor/block-list.js	0% <0%> (ø)	⬆️
editor/utils/url.js	50% <0%> (-16.67%)	⬇️
blocks/library/code/index.js	40% <0%> (-10%)	⬇️
blocks/library/verse/index.js	28.57% <0%> (-8.93%)	⬇️
blocks/library/preformatted/index.js	37.5% <0%> (-6.95%)	⬇️
blocks/library/table/index.js	30% <0%> (-6.37%)	⬇️
blocks/api/paste.js	54.54% <0%> (-5.46%)	⬇️
... and 27 more

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[nylen]

This should be a reasonable foundation for #2191, but I still can't figure out how to get the tests to work using shallow instead of mount. @aduth maybe you can explain what I am missing there?

[nylen]

I've updated this PR by request to remove the tracking code.

[aduth]

If we're removing tracking now, might we also ought remove this component? (YAGNI)

At very least, Popover usage has since changed and has isOpen prop:

https://github.com/WordPress/gutenberg/tree/master/components/popover

[nylen]

Removed in e5f4eec.