HG-515 Fix trackClick action for components

This “bug” was caused by a recent EmberJS upgrade. However, the “bug”
is actually not a bug but a hack on our side. See this link for more
information:
https://github.com/emberjs/ember.js/issues/9541

Actions referenced in components need to be handled by the component,
and will no longer “bubble up” to be handled by the parent
component/controller/route.
HG-515 SiteHeadComponent needs trackClick action
HG-515 Other components that may need trackClick
Let's use mixin for that, and sendAction to bubble this action
Extend only components that use track click
this is not needed here
fix tests
Merge pull request #476 from Wikia/HG-515

Fix trackClick action for components