List consular services by country.

Provides an alphabetical index of countries and their british consular
services including alternatives where no services are offered in that
country.
Fix consular service offices with the wrong office type
Call it an Embassy

The thing we are representing is a view across several models
incorporating a WorldLocation, WorldwideOrganisations, their
WorldwideOffices and the address information. For brevity and convention
I've called this an Embassy.
Tidy up layout and styles
Merge pull request #1714 from alphagov/embassies_index

This is very low risk as it's not currently linked to anywhere on Whitehall or mainstream content.