Google analytics event tracking implementation

As a business user I would like to use Google analytics event tracking facility on my site.

TD:
This task requires analysis and documentation on how we will support GA event tracking.
Please create analysis document first, so that we can review how to proceed with integration (this is because we need to think of best way to integrate it into UI, maybe extracting it into a separate section in marketing?).

Some thoughts/questions:
1. How to allow enabling the analytics (currently on 2.2.0 we proposed to use content includes, maybe we need dedicated attributes in store instead?)
2. Global switch for this feature on per Shop basis
3. What types of events should we be tracking? (e.g. product views, sku views, category views, content views, search requests)
4. How to send data? (client side JS vs server side HTTP)

Client side:
https://developers.google.com/analytics/devguides/collection/gajs/eventTrackerGuide

Measurement protocol (sever-side):
https://developers.google.com/analytics/devguides/collection/protocol/v1/devguide