Consolidate collapse table CSS

Authored by Niedzielski on Apr 21 2017, 2:35 AM.

Description

Consolidate collapse table CSS

Move collapse table to wikimedia-page-library.

https://github.com/wikimedia/wikimedia-page-library/pull/3

Bug: T158309
Change-Id: Ie1848e5543e7ae51431671ad0db189c1e9a42874