Add subject areas concept to resources to help reduce generator time

[shah]

Because not all resources need to be generated all the time, add a subject area or namespace concept that can be configured on a per-resource or per-resource-originator basis that the generator can use to filter or select which resources should be part of the publication process.

This could be accomplished in a few ways:

• [ ] Use existing namespaces strategy
• [ ] Define concept of services or service areas
• [ ] Use concept of modules (not Deno but end-user understandable modules)

export interface SubjectSupplier<Area> extends Namespace<Area> {
    readonly subject: string;
}

export interface SubjectAreaSupplier<Area> {
    readonly subjectArea: SubjectSupplier<Area>;
}