[Mbuilder] [Verboice] Unify phone numbers per country code metric

[bcardiff]

Mbuilder and Verboice currently have:

• Verboice :: number of callers in addressbook per country code
• Mbuilder :: number of unique phone numbers in addressbook per country code

these also have project_id / application_id

• [x] update both names to "numbers of unique phone numbers in project per country code"
• [x] allow old meassures to be received and transformed to new metrics in order to be backward compatible until updates reach application servers.
• [x] migrate of current data
• [x] update charts to use new metric

This metric will allow the detection of the biggest application regarding numbers of country, numbers of phones, numbers of phones per country.

It won't allow accurate analysis of overall reachability across countries.

[bcardiff]

migration of data will need to be manually done upon deployment of telemetry_server. After that, the charts will be able to be updated.

[bcardiff]

@nditada "Unique phone numbers by country and application" was created to show per each country.