Moved labs middleware into labs utility

- this middleware isn't used anywhere at the moment
- including it in our labs utility should help to make it moe discoverable

core/server/web/shared/middlewares/labs.js

@@ -1,12 +0,0 @@
-const errors = require('@tryghost/errors');
-const labsUtil = require('../../../../shared/labs');
-
-const labs = flag => (req, res, next) => {
-    if (labsUtil.isSet(flag) === true) {
-        return next();
-    } else {
-        return next(new errors.NotFoundError());
-    }
-};
-
-module.exports = labs;

core/shared/labs.js

@@ -94,3 +94,11 @@ module.exports.enabledHelper = function enabledHelper(options, callback) {
 
     return errString;
 };
+
+module.exports.enabledMiddleware = flag => (req, res, next) => {
+    if (this.isSet(flag) === true) {
+        return next();
+    } else {
+        return next(new errors.NotFoundError());
+    }
+};