Vector: Add the collapsibleTabs script from the Vector extension

* Move jquery.collapsibleTabs from the Vector extension
  to the Vector skin (see 097f387362)
* Register the module and its dependencies
* Merge the init script into the existing vector.js

Bug: 46513
Change-Id: I7bd77e6e4c384c9e2033f9d05ffcae86b0bb7a69