API for LightClientBootstrap, LightClientFinalityUpdate, LightClientOptimisticUpdate and light client events (#3954)

* rebase and add comment

* conditional test

* test

* optimistic chould be working now

* finality should be working now

* try again

* try again

* clippy fix

* add lc bootstrap beacon api

* add lc optimistic/finality update to events

* fmt

* That error isn't occuring on my computer but I think this should fix it

* Add missing test file

* Update light client types to comply with Altair light client spec.

* Fix test compilation

* Support deserializing light client structures for the Bellatrix fork

* Move `get_light_client_bootstrap` logic to `BeaconChain`. `LightClientBootstrap` API to return `ForkVersionedResponse`.

* Misc fixes.
- log cleanup
- move http_api config mutation to `config::get_config` for consistency
- fix light client API responses

* Add light client bootstrap API test and fix existing ones.

* Fix test for `light-client-server` http api config.

* Appease clippy

* Efficiency improvement when retrieving beacon state.

---------

Co-authored-by: Jimmy Chen <jchen.tc@gmail.com>

lighthouse/tests/beacon_node.rs

@@ -2346,7 +2346,10 @@ fn sync_eth1_chain_disable_deposit_contract_sync_flag() {
 fn light_client_server_default() {
     CommandLineTest::new()
         .run_with_zero_port()
-        .with_config(|config| assert_eq!(config.network.enable_light_client_server, false));
+        .with_config(|config| {
+            assert_eq!(config.network.enable_light_client_server, false);
+            assert_eq!(config.http_api.enable_light_client_server, false);
+        });
 }
 
 #[test]
@@ -2354,7 +2357,20 @@ fn light_client_server_enabled() {
     CommandLineTest::new()
         .flag("light-client-server", None)
         .run_with_zero_port()
-        .with_config(|config| assert_eq!(config.network.enable_light_client_server, true));
+        .with_config(|config| {
+            assert_eq!(config.network.enable_light_client_server, true);
+        });
+}
+
+#[test]
+fn light_client_http_server_enabled() {
+    CommandLineTest::new()
+        .flag("http", None)
+        .flag("light-client-server", None)
+        .run_with_zero_port()
+        .with_config(|config| {
+            assert_eq!(config.http_api.enable_light_client_server, true);
+        });
 }
 
 #[test]