Multimodule Stories

In larger apps, its common to have mamy modules with different feature components.
Each module currently generates a gallery app within its own module (which is fine sometimes) but would love a way to then combine all of the stories into a single gallery app cross my entire application. The only way to do this right now, is to move all of the stories into the main app module, which is not super scalable in larger apps.

Start by locating how each module generates its gallery app and how stories are discovered across modules. Determine how a main application could combine those stories without moving them into the main app module. Done means one gallery app can show stories from multiple feature modules.

Written by the indexing model from the issue text.