[FEATURE] Dual Certificate Configuration

### What's needed and why?

Being able to configure two certificates instead of only one. Maybe check that both certificates are a different type (rsa and ecdsa).

Add support in the letsencrypt feature:

If #3134 gets accepted, key-type needs to be updated to also support `both`. This would also be the preferred way to configure the letsencrypt feature with this.

## Reason
- Be able to ship a rsa cert for compatibility
- Be able to ship a ecdsa cert (I don't think I need to explain why ecdsa is preffered, if available)
- It is a [recommendation from letsencrypt](https://letsencrypt.org/docs/integration-guide/#supported-key-algorithms).

### Implementations ideas (optional)

_No response_

### Code of Conduct

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