Change Android Authenticator package ID

We are stuck for the release of "Android Authenticator" application.

You need 2 things to publish on play store:

A unique application ID (the current one is "org.xwiki.android.authenticator")
An associated publication key

Problem is that we lost the key (we lost contact with Fitz during first GSOC before he get a change to give us the private key he used for the first release) and you can't change the key for an application on play store. We contacted the support to know if we could modify the key but we did not get any answer and since it' not too critical to ditch the old (beta released only) application and create a new one (new from play store point of view) we decided to change the id.

Also note that the Java package we use in the module is "org.xwiki.android.authenticator" which is why we have the current application id.