IdNumber - Dutch BSN generator

[Fonzie-byte]

Motivation / Background

This Pull Request has been created because a generator for Dutch national ID numbers (called Burger Service Nummer, or BSN for short) was missing.

I know you are not looking for new generators, but I hope you will still consider something this useful.

Additional information

Sample terminal output:

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one change. Changes that are unrelated should be opened in separate PRs.
• Commit message has a detailed description of what changed and why. If this PR fixes a related issue include it in the commit message. Ex: [Fix #issue-number]
• Tests are added or updated if you fix a bug, refactor something, or add a feature.
• Tests and Rubocop are passing before submitting your proposed changes.

If you're proposing a new generator or locale:

• Double-check the existing generators documentation to make sure the new generator you want to add doesn't already exist.
• You've reviewed and followed the Contributing guidelines.

[Fonzie-byte]

This was added automatically, and I try to refrain from manually removing lines from the lock file.

Question for the Faker maintainers: Should this change be removed or let it?