Feature publisher

First mojo for the Play store publisher. 

Using the same file structure for store listing, what's new, etc. as the Gradle publisher.
https://github.com/Triple-T/gradle-play-publisher

Can be used inside or outside a project, 

	<android.publisher.email>xxx</android.publisher.email>
        <android.publisher.p12>xxx</android.publisher.p12>

Publisher email and p12 file are required (https://developers.google.com/android-publisher/getting_started).

Close https://github.com/simpligility/android-maven-plugin/issues/418

Co-authored by @Shusshu