Implement a folder filter

[Kingdutch]

The root argument will always need to be the project root to be able to create an inventory of all modules. However, it's not always useful to get duplicates for all modules in a project.

Implement a --folder option to limit for which info.yml files the dependencies are listed.

It should be possible to pass multiple paths. The paths should be absolute or relative to the project root (<directory> argument).