Use new RestClientParameters class instead of BusTopicParams

Policy-endpoints contained a RestServerParameters class for configuring the server side of a REST api, but it did not contain a corresponding RestClientParameters class, thus the various policy components (e.g., pap) ended up using BusTopicParams, instead, which provides little validation support. Now that the RestClientParameters class has been added to policy-endpoints, the components should be modified to use the new class.