ServerUrlPicker
that, descending from the android.os.AsyncTask
class, allows to perform on a background thread the following operations:
browsing the web for web page used as dispenser of the url the JotyApp have to work on, and, then,
by making use of the org.jsoup library, building an org.jsoup.nodes.Document object
and, from this, extracting the url.ActivityController.createRespHandler