Add Android namespace

[ydiev]

No description provided.

[WingCH]

please merge

[anshul-arora]

@ydiev @WingCH
i believe this would not be needed if you use this in your project

allprojects {
....
    subprojects {
        afterEvaluate { project ->
            if (project.hasProperty('android')) {
                project.android {
                    if (namespace == null) {
                        namespace project.group
                    }
                }
            }
        }
    }
}

[Pavlo-Freebee]

@wslaimin pls merge