auth for engine api (#3046)

## Issue Addressed

Resolves #3015 

## Proposed Changes

Add JWT token based authentication to engine api requests. The jwt secret key is read from the provided file and is used to sign tokens that are used for authenticated communication with the EL node.

- [x] Interop with geth (synced `merge-devnet-4` with the `merge-kiln-v2` branch on geth)
- [x] Interop with other EL clients (nethermind on `merge-devnet-4`)
- [x] ~Implement `zeroize` for jwt secrets~
- [x] Add auth server tests with `mock_execution_layer`
- [x] Get auth working with the `execution_engine_integration` tests






Co-authored-by: Paul Hauner <paul@paulhauner.com>

testing/execution_engine_integration/src/test_rig.rs

@@ -46,10 +46,17 @@ impl<E: GenericExecutionEngine> TestRig<E> {
 
         let ee_a = {
             let execution_engine = ExecutionEngine::new(generic_engine.clone());
-            let urls = vec![execution_engine.http_url()];
+            let urls = vec![execution_engine.http_auth_url()];
+
+            let config = execution_layer::Config {
+                execution_endpoints: urls,
+                secret_files: vec![],
+                suggested_fee_recipient: Some(Address::repeat_byte(42)),
+                default_datadir: execution_engine.datadir(),
+                ..Default::default()
+            };
             let execution_layer =
-                ExecutionLayer::from_urls(urls, fee_recipient, executor.clone(), log.clone())
-                    .unwrap();
+                ExecutionLayer::from_config(config, executor.clone(), log.clone()).unwrap();
             ExecutionPair {
                 execution_engine,
                 execution_layer,
@@ -59,8 +66,16 @@ impl<E: GenericExecutionEngine> TestRig<E> {
         let ee_b = {
             let execution_engine = ExecutionEngine::new(generic_engine);
             let urls = vec![execution_engine.http_url()];
+
+            let config = execution_layer::Config {
+                execution_endpoints: urls,
+                secret_files: vec![],
+                suggested_fee_recipient: fee_recipient,
+                default_datadir: execution_engine.datadir(),
+                ..Default::default()
+            };
             let execution_layer =
-                ExecutionLayer::from_urls(urls, fee_recipient, executor, log).unwrap();
+                ExecutionLayer::from_config(config, executor, log.clone()).unwrap();
             ExecutionPair {
                 execution_engine,
                 execution_layer,