Add gendered first names to it and fr-CH locales

[huerlisi]

Motivation / Background

Faker::Name.male_first_name and Faker::Name.female_first_name had no
data in the it and fr-CH locales. Because of that they silently fell
back to the English name list, so a German/Italian/French app asking for a
gendered first name got English names:

Faker::Config.locale = 'it'
Faker::Name.male_first_name    #=> "Barton"
Faker::Name.female_first_name  #=> "Tanesha"

Faker::Config.locale = 'fr-CH'
Faker::Name.male_first_name    #=> "Antonia"
Faker::Name.female_first_name  #=> "Hermina"

This Pull Request adds curated, sex-correct male_first_name /
female_first_name pools to both locales. The change is purely additive:
the existing gender-neutral first_name lists are left untouched, so no
existing behaviour changes.

Additional information

Output after the change:

Faker::Config.locale = 'it'
Faker::Name.male_first_name    #=> "Ivan"
Faker::Name.female_first_name  #=> "Alessandra"

Faker::Config.locale = 'fr-CH'
Faker::Name.male_first_name    #=> "Yann"
Faker::Name.female_first_name  #=> "Zoé"

The added tests assert the generated names are members of the locale's own
lists, 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]

I've created three MRs to add some specific locale data we need in our application.

The MRs touch the same files, so this could lead to conflicts. I can also rework them into a single MR if that's simpler.

I've created these MRs using Claude Code but manually verified. I kept the markers in the commit message. Just tell what your policy regarding AI supported contributions are if this does not work for you.

Thanks for maintaining this gem <3