Add proto_array fork choice (#804)

* Start implementing proto_array

* Add progress

* Add unfinished progress

* Add further progress

* Add progress

* Add tree filtering

* Add half-finished modifications

* Add refactored version

* Tidy, add incomplete LmdGhost impl

* Move impls in LmdGhost trait def

* Remove old reduced_tree fork choice

* Combine two functions in to `compute_deltas`

* Start testing

* Add more compute_deltas tests

* Add fork choice testing

* Add more fork choice testing

* Add more fork choice tests

* Add more testing to proto-array

* Remove old tests

* Modify tests

* Add more tests

* Add more testing

* Add comments and fixes

* Re-organise crate

* Tidy, finish pruning tests

* Add ssz encoding, other pub fns

* Rename lmd_ghost > proto_array_fork_choice

* Integrate proto_array into lighthouse

* Add first pass at fixing filter

* Clean out old comments

* Add more comments

* Attempt to fix prune error

* Adjust TODO

* Fix test compile errors

* Add extra justification change check

* Update cargo.lock

* Fix fork choice test compile errors

* Most remove ffg_update_required

* Fix bug with epoch of attestation votes

* Start adding new test format

* Make fork choice tests declarative

* Create test def concept

* Move test defs into crate

* Add binary, re-org crate

* Shuffle files

* Start adding ffg tests

* Add more fork choice tests

* Add fork choice JSON dumping

* Add more detail to best node error

* Ensure fin+just checkpoints from from same block

* Rename JustificationManager

* Move checkpoint manager into own file

* Tidy

* Add targetted logging for sneaky sync bug

* Fix justified balances bug

* Add cache metrics

* Add metrics for log levels

* Fix bug in checkpoint manager

* Fix compile error in fork choice tests

* Ignore duplicate blocks in fork choice

* Add block to fock choice before db

* Rename on_new_block fn

* Fix spec inconsistency in `CheckpointManager`

* Remove BlockRootTree

* Remove old reduced_tree code fragment

* Add API endpoint for fork choice

* Add more ffg tests

* Remove block_root_tree reminents

* Ensure effective balances are used

* Remove old debugging code, fix API fault

* Add check to ensure parent block is in fork choice

* Update readme dates

* Fix readme

* Tidy checkpoint manager

* Remove fork choice yaml files from repo

* Remove fork choice yaml from repo

* General tidy

* Address majority of Michael's comments

* Tidy bin/lib business

* Remove dangling file

* Undo changes for rpc/handler from master

* Revert "Undo changes for rpc/handler from master"

This reverts commit 876edff0e4.

Co-authored-by: Age Manning <Age@AgeManning.com>

beacon_node/rest_api/src/router.rs

@@ -1,6 +1,6 @@
 use crate::{
-    beacon, consensus, error::ApiError, helpers, metrics, network, node, spec, validator, BoxFut,
-    NetworkChannel,
+    advanced, beacon, consensus, error::ApiError, helpers, metrics, network, node, spec, validator,
+    BoxFut, NetworkChannel,
 };
 use beacon_chain::{BeaconChain, BeaconChainTypes};
 use client_network::Service as NetworkService;
@@ -147,6 +147,11 @@ pub fn route<T: BeaconChainTypes>(
                 into_boxfut(spec::get_eth2_config::<T>(req, eth2_config))
             }
 
+            // Methods for advanced parameters
+            (&Method::GET, "/advanced/fork_choice") => {
+                into_boxfut(advanced::get_fork_choice::<T>(req, beacon_chain))
+            }
+
             (&Method::GET, "/metrics") => into_boxfut(metrics::get_prometheus::<T>(
                 req,
                 beacon_chain,