ParentPublisher and ChildPublisher collections should include roles

[Arlodotexe]

Background

No prior public docs can be found for this. It appears the API design discussion/docs for Publisher getting ChildPublisher and ParentPublisher properties is missing. It occurred between WindowsAppCommunity/uwpcommunity-backend#144 and #2

The inbox members on a Publisher include collections for ParentPublishers and ChildPublishers. Through mutual linkback, the idea with these was to enable representation of:

1. "Organization" hierarchies
   • Should be capable of importing/syncing from a GitHub org
   • Should be capable of representing many project-level teams in a single org and many org-level teams within a larger org.
2. Cross-publisher partnerships, community hubs
   • The Publisher entity is designed to be usable by anyone who pushes project content to users
   • This also includes our "Windows App Community" Discord server, which acts as a "hub" for publishers and users to discover each other and collaborate.
   • With a publisher capable of representing any Discord server with registered users, projects and/or publishers, Discord servers of existing publishers in our community can reuse the SDK in a bot and access/update all of their data fully p2p.

Problem

Because the collections for ChildPublisher and ParentPublisher are only Publisher collections without role data, there's no way to differentiate between organizational hierarchies and community registration.

Solution

Role data needs to be included on these collections.

• IModifiablePublisher.ChildPublisher and IModifiablePublisher.ParentPublisher need to be changed from type IModifiablePublisherCollection<IReadOnlyPublisher> to type IModifiablePublisherRoleCollection (or possibly IModifiablePublisherCollection<IReadOnlyPublisherRole>)
• IReadOnlyPublisher.ChildPublisher and IReadOnlyPublisher.ParentPublisher need to be changed from type IReadOnlyPublisherCollection to type IReadOnlyPublisherRoleCollection.
• Implementations need to be updated accordingly.