generateContributionProviders
When enabled, generates top-level contribution provider classes with @Provides functions instead of nested binding containers with @Binds callables for @ContributesBinding, @ContributesIntoSet, and @ContributesIntoMap.
This works by wholly encapsulating the injected class behind a @Provides declaration, which hides it from the graph and only exposes the bound type.
A side benefit of this is that this allows implementation classes to remain internal since the generated provider directly constructs them (which in turn allows for finer-grained IC).
Disabled by default.