chore(tslib): optimize imports

[layershifter]

This PR adds importHelpers option and allows us to drastically reduce bundle size 🚀 It will import emit helpers (e.g. __extends, __rest, etc..) from tslib, similar to @babel/runtime.

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Measures are taken from our UMD bundle as it contains all components.

Before: 723KB
After: 681KB (-42KB/-~6%)

[codecov]

Codecov Report

Merging #1184 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1184   +/-   ##
=======================================
  Coverage   82.47%   82.47%           
=======================================
  Files         740      740           
  Lines        8754     8754           
  Branches     1170     1236   +66     
=======================================
  Hits         7220     7220           
  Misses       1519     1519           
  Partials       15       15

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[DustyTheBot]

	Warnings
⚠️	Package (or peer) dependencies changed. Make sure you have approval before merging!

Changed dependencies in packages/react/package.json

package	before	after
tslib	-	^1.9.3

Changed dependencies in packages/react-component-nesting-registry/package.json

package	before	after
tslib	-	^1.9.3

Changed dependencies in packages/react-proptypes/package.json

package	before	after
tslib	-	^1.9.3

Changed dependencies in packages/react-component-event-listener/package.json

package	before	after
tslib	-	^1.9.3

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