Templates for mw ext qunit and qunit-mobile jobs

Change-Id: I2bc8281194028626afa01e78c3dbc6f01c88bf19
Apply qunit template where relevant

Trigger mwext-TemplateData-jslint again, it got removed beginning of
june.

As a side effect: adds mediawiki-core-extensions-integration to the
experimental pipeline.

Change-Id: I9bb3ccd9705bfca62ed604341af2b342792521d8
Qunit jobs for Popups extension

Bug: 67022
Change-Id: I319c81bf3fe9e91028ca8aa2286a2ab799d62a4a