Allow to define a base "namespace" in deptective.json

[gunnarmorling]

Given that most of the packages of a code base share one or more common base packages, it'd avoid quite some typing in deptective.json if one could define a "namespace" or similar, and all other packages would be resolved relative to that base name. E.g.:

{
    "namespace" : "org.mapstruct",
    "components": [
        {
            "name": "org.mapstruct.ap",
            "contains": [ "ap" ],
            "reads": [
                "org.mapstruct.ap.internal.model",
                "org.mapstruct.ap.internal.option",
                "org.mapstruct.ap.internal.prism",
                "org.mapstruct.ap.internal.processor",
                "org.mapstruct.ap.internal.util",
                "org.mapstruct.ap.spi"
            ]
        },
        {
            "name": "org.mapstruct.ap.internal.conversion",
            "contains": [ "internal.conversion" ],
            "reads": [
                "org.mapstruct.ap.internal.model",
                "org.mapstruct.ap.internal.util"
            ]
        },
        ...