OPENEUROPA-1370: Replace the functional tests with Behat in OE Media.

[sergepavle]

OPENEUROPA-1370

Description

In the OE Media component we have some functional javascript tests. These should instead be Behat tests agains the demo module to illustrate the provided capabilities in a way in which business can also understand what the component can offer.
h2. To do:

• Replace the 4 Functional JS tests with Behat tests like the ones that already exist
• Replace the "And I remove the media" cleanup tests with an automatic way of doing it:

• Before and after scenario with a tag: preserveMedia
• Before scenario that has the tag will keep track of the last Media entity ID
• After scenario that has the tag deletes all the media entities with IDs higher than the one that was last

• In the media-avportal-entity-browser feature, remove the empty lines at the end of the file (except the last one) -> this is a minor cleanup

[nagyad]

Good job!