refactor: use appmodule.AppModule in new API

[julienrbrt]

Description

Investigate how we can increase the usage of appmodule.AppModule instead of module.AppModule thorough the codebase.

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[julienrbrt]

Most of the changes here will be reverted, but it easier to check where AppModuleBasic is really directly required.

[julienrbrt]

From where this is going, I think this is too early. I'll go with the proposed solution from @tac0turtle, with a tweak of not adding an extension interface, but having the basic manager check the interface directly.