New Feature: Phone codes

[Alexuy]

What do you think about PhoneCode class? Maybe add to lib phone code and relation with countries?

[eugen-fried]

+1 on this issue. It would be nice to have the support in my project. Will a pull request with country codes be welcomed if I do it myself?

[heruan]

This is definitely needed! Getting the international phone prefix from CountryCode would be also very useful to avoid redundant fields.

@TakahikoKawasaki what do you think?

[altro3]

@heruan As you see, I suggested it 5 years ago (yes, it was my second account).

I think, you can predict his answer :-)

[TakahikoKawasaki]

Could anyone make a pull request?