feat: add --env=production flag to node ace generate:key

[NathaelB]

❓ Type of change

• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

This pull request introduces a new --env=production flag to the node ace generate:key command.

Key Changes:

• When the commande is run with the --end=production flag, the APP_KEY in .env.example is cleared (set to an empty value).
• Simultaneously, the APP_KEY in the .env file is updated with a new, randomly generated key, ensuring the correct key for the production environment is set.

Why is this change required?
This enhancement simplifies key management for production environments by automatically clearing the APP_KEY in .env.example, reducing the risk of accidentally committing sensitive keys. It also ensures that a new key is generated and set directly in .env without manual intervention.

[RomainLanz]

Hey! 👋🏻

Thanks for the PR! This change has already been addressed in #4722, and I don't think we need a flag to toggle copying the value in the example file.