... and attach the split payload writer variant to the pxar archive creation. By this, metadata and payload data will create different dynamic indexes, allowing to lookup and reuse payload chunks without the additional overhead of the pxar archive's metadata. For now this functionality remains disabled and will be enabled in a later patch once the logic for reusing the payload chunks is in place. Signed-off-by: Christian Ebner <c.ebner@proxmox.com>