Notifications functionality needs to be updated

Connected with: https://github.com/openMF/web-app/issues/1228

I am facing the following issues:

• API doesn't return appropriate notifications for `isRead` parameter ie: setting it to false still returns notifs with `isRead=true`
• With the present structure of routing in web app we need parent Id attribute to come along with notifications data for eg: for "loan created" notification we need client Id as well.
• Cannot confirm whether notifications update with a `PUT` request on /notifications.
• Please see this file for API calls: https://github.com/openMF/web-app/blob/master/src/app/notifications/notifications.service.ts