Remove foundation accordion from sidebar - we already handle this with custom js

Summary:
This was causing intermittent broken accordions in the sidebar whenever the
foundation js actually worked. We already have custom handling for this in
WorkspaceView and don't need foundation accordion's JS, just the styling.

Test Plan: - Load UI and check that workspace accordions work as expected.

Reviewers: seth, shadowhand

Reviewed By: shadowhand

Differential Revision: https://phabricator.ushahidi.com/D159