Altair consensus changes and refactors (#2279)

## Proposed Changes

Implement the consensus changes necessary for the upcoming Altair hard fork.

## Additional Info

This is quite a heavy refactor, with pivotal types like the `BeaconState` and `BeaconBlock` changing from structs to enums. This ripples through the whole codebase with field accesses changing to methods, e.g. `state.slot` => `state.slot()`.


Co-authored-by: realbigsean <seananderson33@gmail.com>

validator_client/src/http_api/mod.rs

@@ -16,7 +16,7 @@ use std::net::{Ipv4Addr, SocketAddr, SocketAddrV4};
 use std::path::PathBuf;
 use std::sync::{Arc, Weak};
 use tokio::runtime::Runtime;
-use types::{ChainSpec, EthSpec, YamlConfig};
+use types::{ChainSpec, ConfigAndPreset, EthSpec};
 use validator_dir::Builder as ValidatorDirBuilder;
 use warp::{
     http::{
@@ -191,9 +191,9 @@ pub fn serve<T: 'static + SlotClock + Clone, E: EthSpec>(
         .and(signer.clone())
         .and_then(|spec: Arc<_>, signer| {
             blocking_signed_json_task(signer, move || {
-                Ok(api_types::GenericResponse::from(
-                    YamlConfig::from_spec::<E>(&spec),
-                ))
+                let mut config = ConfigAndPreset::from_chain_spec::<E>(&spec);
+                config.make_backwards_compat(&spec);
+                Ok(api_types::GenericResponse::from(config))
             })
         });
 

validator_client/src/http_api/tests.rs

@@ -150,7 +150,8 @@ impl ApiTester {
     pub async fn test_get_lighthouse_spec(self) -> Self {
         let result = self.client.get_lighthouse_spec().await.unwrap().data;
 
-        let expected = YamlConfig::from_spec::<E>(&E::default_spec());
+        let mut expected = ConfigAndPreset::from_chain_spec::<E>(&E::default_spec());
+        expected.make_backwards_compat(&E::default_spec());
 
         assert_eq!(result, expected);