Revert "Merge pull request #2734 from guardian/chartbeat-hotfix"

This reverts commit e51e318f63cfb09edcf5b50dc079ffea7592b928, reversing
changes made to 126c0f7553dd30bfcaab70a812b60183bd588d89.

Conflicts:
	common/app/views/fragments/commonJavaScriptSetup.scala.html
Revert "Merge pull request #2716 from guardian/chartbeat-desktop-test"

This reverts commit 0b456bc5857e8e0bd36850a53e85fc61e9fa4972, reversing
changes made to 872f4cd64b08633c18546a8ad81405084f557f88.

Conflicts:
	common/app/assets/javascripts/modules/experiments/ab.js
	common/app/conf/switches.scala
Remove commercial-in-article-* AB tests
Merge branch 'master' of https://github.com/guardian/frontend into revert-chartbeat-and-commercial-tests

Conflicts:
	common/app/assets/javascripts/modules/experiments/ab.js
	common/app/conf/switches.scala
Merge conflict - remove userzoom
Merge pull request #2867 from guardian/revert-chartbeat-and-commercial-tests

Revert chartbeat and commercial tests