Revert "Install phantomjs on devserver role"

Summary:
Not maintained anymore, not required by foundation-zurb-template,
other alternatives exist like headless Firefox/Chromium.

Fixes T1565.

This reverts commit b3ef1c37924711ef68db46ba694a772eeb17b2a4.

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1565

Differential Revision: https://devcentral.nasqueron.org/D2130