Provide ability to specify Web Origins to be added to RH SSO client config

It is sometimes desirable to configure the Web Origins field on clients in RH SSO. This allows for CORS to be enabled and to allow support for SwaggerUI integration with RH SSO in ActiveDocs.

See the Web Origins section in the RH SSO documentation for more information.
https://access.redhat.com/documentation/en-us/red_hat_single_sign-on/7.2/html-single/server_administration_guide/index#oidc_clients

To prevent the need for manually updating each new client in RH SSO that is synced from 3scale, it would useful to be able to configure the default value from the service configuration page, similar to the default OIDC flows. Then zync could set this field automatically.