add remove-fpt helper function

lib/remove-fpt-from-path.js

@@ -0,0 +1,9 @@
+const slash = require('slash')
+const nonEnterpriseDefaultVersion = require('./non-enterprise-default-version')
+
+// This is a convenience function to remove free-pro-team@latest from all
+// **user-facing** aspects of the site (particularly URLs) while continuing to support
+// free-pro-team@latest as a version both in the codebase and in content/data files.
+module.exports = function removeFPTFromPath (path) {
+  return slash(path.replace(`/${nonEnterpriseDefaultVersion}`, ''))
+}