Provide a service for statistics

[gregorwolf]

It should be easy to get the total number of Events, Organizers, CoOrganizers, Attendees, Cancelations

[seVladimirs]

do you have any dummy data which we can use for a baseline? Otherwise, we would need to fill it manually.

[gregorwolf]

If you run the automated tests as described in https://github.com/sapmentors/SITreg/tree/master/test you should get 3 events with some participants.