Cover ezstudio-demo-bundle bundle with some behat scenarios.

Question: Do we need the same for ezstudio-demo-bundle-data bundle? No.
Note: To be discussed with Damian Z.

Remarks: StudioUI suite covers the back office, from web team perspective testing the front-end is important.
StudioUI suite was replaced with the (small) suites for FlexWf, DateBasedPublisher and Form builder Page part (which are also for the back office).