Aggregate dependency scopes

[Gabriel-Darbord]

The same dependency can exist in multiple scopes (this happens a lot with Gradle).
Instead of having to choose one when flattening, and also when adding it to each subproject's dependencies, only one dependency should exist with multiple scopes.

dependencies:
  - group:   <dependencyGroup>
    name:    <dependencyName>
    version: <dependencyVersion>
    scopes:  [<dependencyScope>, ...]
    type:    <dependencyType>