Created Jenkins job that runs MultimediaViewer Selenium tests

I have created just one job for the moment, running at
en.wikipedia.beta.wmflabs.org using Firefox:

https://wmf.ci.cloudbees.com/view/r-mv/

E-mail notifications are
sent to Aaron, Chris, Jeff and me (Željko).

Also added missing repositories (ContentTranslation, Wikibase) to the
Jenkins job template and moved browsertests to the bottom.

Bug: 60267
Change-Id: Ife8b52402d5dd4b96e7f198077d8b4457e361a7f