Renaming middleware reqdata.js to reslocals.js and adding req.session.user

 - Renames `server/middleware/reqdata.js` to `server/middleware/reslocals.js`.
 - Adding the entry `user: req.session.user` to the new `reslocals.js` file.
 - Changing the `app.js` middleware stack to use the new `reslocals` name.