FileUpload options for Server Config (#7071)

* New: fileUpload options to restrict file uploads

* review changes

* update review

* Update helper.js

* added complete fileUpload values for tests

* fixed config validation

* allow file upload only for authenicated user by default

* fixed inconsistent error messages

* consolidated and extended tests

* minor compacting

* removed irregular whitespace

* added changelog entry

* always allow file upload with master key

* fix lint

* removed fit

Co-authored-by: Manuel Trezza <trezza.m@gmail.com>

spec/helper.js

@@ -88,6 +88,11 @@ const defaultConfiguration = {
   fileKey: 'test',
   silent,
   logLevel,
+  fileUpload: {
+    enableForPublic: true,
+    enableForAnonymousUser: true,
+    enableForAuthenticatedUser: true,
+  },
   push: {
     android: {
       senderId: 'yolo',