[WIP] [PULLTHROUGH] Use AceEditorWidget from core

Authored by Jdforrester-WMF on Nov 10 2016, 7:39 PM.

Description

[WIP] [PULLTHROUGH] Use AceEditorWidget from core

Depends-On: I4b3b1a41c2444a38cb3705fa4989d4e5e2e74272
Change-Id: I06cd4cb04bd3d86f3e3260a0826caada3da50cc4