Modify IResource.Parameters

[avanderhoorn]

I propose that we update IResource.Parameters from an IEnumerable<ResourceParameter> to string. Currently, most of our IResourceStartups are implemented because they want a custom Template. We can still support IEnumerable<ResourceParameter> but the user will call parameters.GenerateUriTemplate() to produce the template in order to provide a string. This means more often than not we can have people IResources used which can port to SystemWeb unlike IResourceStartups.

@nikmd23

[nikmd23]

I can get behind this. Let's do it.