The current UI framework needs to be modified to support extensibility. The changes include:

1. Each entity should be defined as a class. The class needs to be registered into a registry. An entity can be extended by creating a subclass of the original entity and override the registration.
2. Facets and dialogs should be defined and registered inside a method in the entity class. A facet/dialog can be extended by creating a custom facet/dialog subclass and override the registration in the custom entity class.
3. There should be an empty JS file to put the UI extensions. The extension will need to be deployed in all IPA server instance.