Merge branch 'codingweekendfs18' of https://gitlab.ethz.ch/amiv/amiv-admintool into codingweekendfs18

page to view events and drop down details

In order to be able to refresh single data lists (e.g. the groupmemberships after
a membership got added), this commit disentangles data from view and enables the
outside userTool to refresh single lists.

- authentication will not check every time but simple catch an authenticated request
- api communication is separated from view definitions