Refactor entry state toggle (#48)

* chore(editorialFeatures): extract editorial features toggle

* chore(refactor): rename function to make more contextual sense

lib/should-attach-entry-state.js

@@ -0,0 +1,3 @@
+module.exports = (response) => {
+  return response.locals.settings.editorialFeatures && response.locals.currentApi.id === 'cpa'
+}