Add Arabic list of countries + Add Palestine to list of countries

This pull request adds:
- sorted list of Arabic countries (tested, and works well with docs/country.html). I named it as countries.ar.js instead of ar_<COUNTRY_CODE> since this applies to all Arab countries.
- Adds Palestine to some lists that were missing it, including en_US, es_ES, it_IT, pt_BR). The rest of de_DE had it already.