feat: Use JSON-RPC for core <> prover interaction (#3626)

## What ❔

Implement communication between proof data handler and gateway through
web sockets.
The workflow:
 * Long-living connection is established
 * Data handler subscribes for proofs from gateway
 * Data handler sends proof generation data to gateway
* On receiving proofs through subscription, data handler saves it's data
and sends a notification to gateway, that proof was successfully
received(to not lose the data in between)

## Why ❔

For the sake of prover cluster, where we will have a single prover
subsystem with multiple sequencers.

## Is this a breaking change?
- [x] Yes
- [ ] No

## Operational changes
Config values:
Prover gateway: ws_port
Proof data handler: api_url, batch_readiness_check_interval_in_secs,
retry_connection_interval_in_secs

## Checklist

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- [ ] PR title corresponds to the body of PR (we generate changelog
entries from PRs).
- [ ] Tests for the changes have been added / updated.
- [ ] Documentation comments have been added / updated.
- [ ] Code has been formatted via `zkstack dev fmt` and `zkstack dev
lint`.

Author: Artemka374

zkstack_cli/crates/zkstack/src/commands/chain/init/configs.rs

@@ -68,6 +68,13 @@ pub async fn init_configs(
         general_config.insert("prover_gateway.api_url", format!("http://127.0.0.1:{port}"))?;
     }
 
+    let prover_gateway_port = general_config
+        .base()
+        .get_opt::<u16>("prover_gateway.ws_port")?;
+    if let Some(port) = prover_gateway_port {
+        general_config.insert("data_handler.api_url", format!("ws://127.0.0.1:{port}"))?;
+    }
+
     let consensus_keys = generate_consensus_keys();
     set_genesis_specs(&mut general_config, chain_config, &consensus_keys)?;