Add interpolation for app.gradle applicationId value in android projects

[petekanev]

Change applicationId field in app.gradle for android projects
Need to add a Grade Android.defaultConfig #454

ping: @rosen-vladimirov @enchev @Plamen5kov

[enchev]

👍

[ghost]

@Pip3r4o There's a big problem with this; it interpolates in the App_Resources folder instead of the platform folder so it's not reusable..

[petekanev]

@vbresults one might call that a problem, another - a feature and intended behavior.

If you believe this to be a problem, please open an issue, stating why you think so, and how you think it should be implemented instead.

As of the current NativeScript version, the app.gradle is interpolated inside the App_Resources, and will not be copied over to platforms/android for additional transformations and interpolations. The file is left entirely in the application author's control beyond the initial interpolation to set a default value for the package name. The team is working on additional features and ways to change that value using json config file. pinging @KristianDD as he might be able to share more about that.