Add gl_ES (Galician) locale

[apeleteiro]

What is the reason for this PR?

• A new feature
• Fixed an issue (resolve #ID)

Author's checklist

• Follow the Contribution Guide
• New features and changes are documented

Summary of changes

Adds a new gl_ES locale for the Galician language (Galicia, Spain).

New providers in src/Provider/gl_ES/:

• Person: first names common in Galicia, mixing Spanish forms (Manuel, María, Josefa…) and traditional Galician forms (Xoán, Brais, Uxía, Sabela…), plus frequent Galician surnames. Names use two surnames, as is usual in Spain. Titles are Sr./D./Dr. and Sra./D.ª/Dra.. dni() reuses the es_ES algorithm; licenceCode() returns Spanish driving licence classes.
• Address: official Galician names of Galician municipalities (concellos), Galician street types (Rúa, Praza, Camiño, Rolda…), postcodes restricted to the four Galician provinces (15, 27, 32, 36), state() returning A Coruña/Lugo/Ourense/Pontevedra, and country names in Galician.
• PhoneNumber: extends es_ES\PhoneNumber, with landlines restricted to the Galician prefixes 981, 982, 986 and 988.
• Company: Galician company name formats (e instead of y, e Fillos), typical prefixes (Conservas, Adegas, Obradoiro…) and suffixes (S.L., S.A., S.Coop.Galega).
• Internet: common email providers in Galicia and the .gal TLD.
• Payment: extends es_ES\Payment (Spanish IBAN and CIF).
• Color: colour names in Galician.

Tests added in test/Provider/gl_ES/ for Person (DNI check letter, licence code, name format), Address (postcode, province, single-line address) and PhoneNumber (Galician prefix).

Documentation PR: FakerPHP/fakerphp.github.io#133

Review checklist

• All checks have passed
• Changes are added to the CHANGELOG.md
• Changes are approved by maintainer

[pwsdotru]

This is not mistake? For Address test needed Person information?

[apeleteiro]

It's intentional: gl_ES\Address::$streetNameFormats uses {{firstName}} and {{lastName}}, which are provided by the Person provider. Without it, address() throws InvalidArgumentException: Unknown format "firstName", so testAddressIsSingleLine() needs it. pt_PT\AddressTest does the same for the same reason.