Localize Faker::Job for de, de-CH, fr, fr-CH and it

[huerlisi]

Motivation / Background

Faker::Job only had data for en (and hy, pt-BR), so every other
locale silently returned English job titles:

Faker::Config.locale = 'it'
Faker::Job.title  #=> "Lead Banking Developer"

Faker::Config.locale = 'de'
Faker::Job.title  #=> "Design Administrator"

This Pull Request adds localized job data for the German, French and
Italian locales. Each provides the keys Faker::Job consumes — field,
seniority, position, key_skills — plus a title template reordered
to fit the language (adjective-after-noun for fr/it). As with the English
generator, titles are synthetic combinations.

Additional information

Output after the change:

Faker::Config.locale = 'de'
Faker::Job.title  #=> "Senior Produktion Planer"

Faker::Config.locale = 'fr'
Faker::Job.title  #=> "Directeur Régional"

Faker::Config.locale = 'fr-CH'
Faker::Job.title  #=> "Responsable Technologie"

Faker::Config.locale = 'it'
Faker::Job.title  #=> "Dirigente Contabilità"

Notes:

• fr follows the lib/locales/fr/ subfolder convention (new
  fr/job.yml); the other locales get a top-level job: block.
• de-CH / fr-CH carry their own copies because they do not fall back to
  de / fr.
• Only the keys consumed by Faker::Job are included (employment_type /
  education_level are not read by any Faker::Job method).

Tests assert Faker::Job.field is a member of the locale's own field list,
guarding against a regression back to the English fallback.

Checklist

• This Pull Request is related to one change.
• Commit message has a detailed description of what changed and why.
• Tests are added or updated.
• Tests and Rubocop are passing before submitting your proposed changes.

[huerlisi]

In the fr locale job.yml is it's own file. The other touched locales don't follow this pattern, but the docs mention this as preferable.

Should I keep as is, or is this the right moment to introduce a directory for the locales I touched?