Prevent voiding a Person linked to Provider(s) and/or User(s) metadata

Currently a user can void a person in the system who is still a provider or user. This causes NullPointerExceptions to client modules/code trying to display Person details (names) from the available providers.

To see this in action set an existing person as a provider, void the person and then visit the provider homepage(/admin/provider/index.htm), you'll notice a javascript error.

The suggested solution is:
i. Prevent voiding of a person if the person is still linked to a user and/or provider.
ii. Provide a descriptive message why the person cannot be voided by listing the user(s) and/or provider(s) preventing the action