GroupData and macro updates

[exe-boss]

We should also move GroupData and similar into mdn-data , which is mentioned in the KumaScript Macro Massacre spreadsheet.

Next steps for KumaScript

Notes from MDN London meeting, September 2018. Problems with current KumaScript Untested code that is used by thousands of pages No comments, documentation or specification for macros Too many macros Too much duplication of code Bad organization (“module” macros, lumped in data, l10n) L10n of text means editing code, which can lead to fall out No portability (e.g. compat table rendering outside of KS) A one line change in a “data macro” can cause fall out The repository has no clear maintainer…