Interests and Topic feature modules should be merged

[dturner]

Previously we had an authors module so the module structure was:

• interests
  • authors
  • topics

Now that we no longer have authors, the nested structure adds complexity for no benefit, making it especially difficult to understand the navigation graph. Suggest merging :topics into :interests (whilst keeping the Topic model).

This would enable InterestsListDetailScreen which is currently in the :app module to be moved into the feature module.

[Jaehwa-Noh]

The merged two modules, seemed too big and coarse grained to me. What about just moving InterestListDetailScreen and Interests2PaneViewModel into :interests?