Add JvmStatic annotations for static functions

[AfzalivE]

For Java interoperability, please add @JvmStatic annotations on static functions.

[pandelisgreen13]

You can use it with Nammu.INSTANCE ,
ex: Nammu.INSTANCE.onRequestPermissionsResult(requestCode, permissions, grantResults);

[tajchert]

I'm open to PR, if not I will try to do in some time later