Set default locales without territory for Portuguese and Italian

It is an established best practice to provide location information even when only a client's language can be detected, and not their territory. This is the way the German locale already works, providing 'de' as language key will find the locale. Similarly, for 'en' there is a default 'en' locale (defaulting to en-GB) and two locales for GB and US territory.

However, the following locales have no default currently:
* it (it-IT)
* pt (pt-PT, pt-BR)