Create a Guided Tour for Media Viewer
completed by: ☃ unicodesnowman
mentors: Gergő Tisza
Create a tour for MediaViewer. Put an "Interactive tour" in the footer to activate the tour. The tour should point out the following features of MediaViewer:
* close button
* metadata panel
Where applicable, make that feature appear while explaining it in the popup.
This is T77726 in Wikimedia's issue tracker.
Students are required to read Wikimedia's general instructions first.