Add Notifications collection and add/modify APIs to add notification view functionality#322

Sebastian-Webster wants to merge 38 commits intomainSquareTable/SocialSquare-Backend:mainfrom

321-add-notification-collection-and-apis-to-retrieve-and-delete-notificationsSquareTable/SocialSquare-Backend:321-add-notification-collection-and-apis-to-retrieve-and-delete-notificationsCopy head branch name to clipboard