Hk object storage encryption documentation overhaul

[KebirHakim]

This pull request updates the French documentation located at pages/storage_and_backup/object_storage/s3_encrypt_your_objects_with_sse_c_and_sse_s3/guide.fr-fr.md. The draft s3_encrypt_your_objects_with_sse_c has been finalized and is now available. The updated content provides detailed guidance on implementing server-side encryption with SSE-C (Server-Side Encryption with Customer Keys) and SSE-S3 (Server-Side Encryption with S3-Managed Keys) for object storage on OVHcloud S3. This enhancement aims to improve security measures and user understanding of encryption options available on OVHcloud S3.