Add Matomo analytics to story telling

Now that we have a Matomo set up, we should add the analytics/metrics tracking to the Story Telling tool. The purpose is to improve the tool and understand which browsers and devices to support.

The most important site at the moment is the AIHEC one, as it is in active use. However, something to consider is if all of the story telling sites should share a analytics or if they should be registered individually.