DAR-1778 Cleanup Hubs tracking params

* changed eventname to wikiahubs ( this is what the processor is looking for
  - see /lib/Wikia/DW/Event/FileParser.pm in analytics repo )
* removed unnecessary passing of content language (it's already passed)
* removed redundant fields (user name and page title)
Merge pull request #1528 from Wikia/DAR-1778

DAR-1778 Cleanup Hubs tracking params