Preparatory Work for Smaller user doc (WIP) (#10245)

* protect all paths in user.pre(save using this.isDirectSelected to see if a field is available

* fix linting

* authWithHeaders: specify user fields to exclude instead of the ones to include, add comments, doc and improve test

* add more options to unit helper generateReq and add tests for excluding fields in authWithHeaders

test/api/v3/integration/user/GET-user.test.js

@@ -34,6 +34,8 @@ describe('GET /user', () => {
     expect(returnedUser._id).to.equal(user._id);
     expect(returnedUser.achievements).to.exist;
     expect(returnedUser.items.mounts).to.exist;
+    // Notifications are always returned
+    expect(returnedUser.notifications).to.exist;
     expect(returnedUser.stats).to.not.exist;
   });
 });