Client-side random request / service ID

Currently `ServiceDeliveranceRequest` is the following:

```
/// A service deliverance request attached with unblinded authenticated credential sent by a peer.
pub struct ServiceDeliveranceRequest {
pub credentials: Vec,
pub signatures: Vec,
pub service_id: u64,
pub commitment_sig: Signature,
}
```

The `service_id` can be included in a stream of protocol-specific message to allow binding between control plane and data plane (e.g assigning credential to a sequence of HTLCs or nostr events where the same `service_id` tag is included). Uncertainty on the confidentiality property of such tagging / pairing.