Bug 877718 - [Messages] Contact's correct phone number and type is displayed

https://bugzilla.mozilla.org/show_bug.cgi?id=877718

Part 1:
    - Implement a desktop version of navigator.mozPhoneNumberService
    - Move all desktop-specific code into js/desktop-only/
    - Updates startup.js to include new dir locations and mock files

The following files are copied almost exactly from https://mxr.mozilla.org/mozilla-central/source/dom/phonenumberutils:

- PhoneNumber.js
- PhoneNumberNormalizer.js
- PhoneNumberMetaData.js
- mcc_iso3166_table.js

Signed-off-by: Rick Waldron <waldron.rick@gmail.com>