PLUGIN-67 Google Analytics 360 (SaaS source) IT

[ghost]

Jira: https://issues.cask.co/browse/PLUGIN-67
Wiki: https://wiki.cask.co/display/CE/Google+Analytics+360

Tests require following system properties:
ga.authorization.token - Authorization token to access Google Analytics reporting API
ga.view.id - The Google Analytics view ID from which the data is retrieved
ga.date.start - Start date for the report data
ga.date.end - End date for the report data
ga.metrics - Quantitative measurements

[ghost]

@albertshau, @CuriousVini, @mikkin could you please review this PR?

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CLAs look good, thanks!

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