Pulp

1. Create a new MasterModel named Distribution. This would have these fields:

   • All the existing fields from BaseDistribution see here.
   • Include all of the fields from the PublicationDistribution and RepositoryVersionDistribution models also, this includes the: publication, repository, and repository_version fields

2. Create corresponding Serializer and Viewset. These will be similar to the BaseDistributionSerializer and BaseDistributionViewset.

3. Handle the pulpcore code that deals with these detail types to ensure a mixutre of detail inheriting from BaseDistribution and Distribution can cooperate together.

   • base path overlap, the code here needs to be updated for both models to consider base path overlaps from both models.
   • name field uniqueness. We need to have uniqueness of the name apply across both models
   • The content app needs to be prepared to read/handle data from both BaseDistribution and Distribution.

NOTE: while doing this work, the author should also implement https://pulp.plan.io/issues/8387 at the same time.