Bug 14868: Display required permissions in permission error response

Bug 14868: Display required permissions in permission error response

When user does not have required permissions to use API operation, it would be
useful to let them know which permissions he is missing. Since they are now
defined in Swagger, we can easily render them into the response.

To test:
1. Use a patron without any permissions
2. Make GET request to http://yourlib/api/v1/patrons
3. Observe permission error and see that required_permissions are displayed.
4. Run t/db_dependent/api/v1/patrons.t

Signed-off-by: Benjamin Rokseth <benjamin.rokseth@kul.oslo.kommune.no>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>