Introduce analytics service infrastructure and base implementation for Google Analytics

The analytics infrastructure within OpenOLAT is weak. Compared to well known analytics tools such as Google Analytics for web pages the course statistics has not a lot to offer. Specially to get an overall impression about the site usage the internal tools doe not offer much.

A new analytics service should help solving this problem. The infrastructure is build to be extensible, however for the initial implementation only a provider to Google Analytics is implemented. 

To use the new tool you need a Google Analytics account and create a Tracking-ID for your OpenOLAT installation. This ID can be configured in the admin environment in the "external tools" section. Once configured, Google Analytics will show where your users spend most of the time, which browsers they use, if they are on a smartphone etc. It also offers a very cool "real-time" analysis.