* Add permissions to Database & add "User"-classes
* Add UI & API for Permissions, protect "User"-(Api)-Controller with new permissions.
* Add some permissions.
* Add permission localization
* Add error handling.
* Error pages: only redirect on 404
* ExceptionController: return JSON-Response on api-routes
* Rename PRODUCT_ADD to PRODUCT_PURCHASE
* Move translation to new file
* Fix checkboxes stay selected on reload.
* Remove configurable User-implementation
* Remove MASTER_DATA_READ
* Disable buttons the user isn't allowed to use.
* Add default permissions for new users
* When migration to permissions, everyone starts as ADMIN
* Permission-Localization: add to transifex & LocalizationService
* Review
Co-authored-by: Bernd Bestel <bernd@berrnd.de>
