Improve the visual of lists of events

Both in mweb_events/events/index and in space_events/index.
Now the lists use the "list-text" style, not "thumbnails" anymore.

Also, 'content-block-footer' now has no border nor background color. To use
the old visual there's a new class 'content-block-footer-fancy'.
Prevent test shibboleth data from leaking in production

Just made sure the test data will only be added to the session in
development mode.