Fix it-IT localization

The it-IT localization for the app is quite poor. These are some of the issues I've seen in there:
 * Inconsistencies within the app, with the Wear app, and with established Android tone/strings
 * Excessive string length
 * Misinterpretations (and thus mistranslations)
 * Weird sounding phrases
 * Unused, missing and non-matching strings

This PR improves the localisation, fixing the aforementioned issues. Also included is a reformatting of the it-IT strings files, as the indentation was quite broken, and a general cleanup (including reordering the strings to match the base strings file).