Expose GRANDPA round state through RPC (#5375)

* grandpa: wire up basic RPC call

* grandpa: make it compile against GRANDPA with expose round state

* grandpa: use shared voter state to expose RPC endpoint

* grandpa: restructure into nested structs

* grandpa: return background rounds too

* grandpa: return error when endpoint not ready

* grandpa: collect grandpa rpc deps

* grandpa: decide to use concrete AuthorityId in finality-grandpa-rpc

* grandpa: remove unncessary type annotation

* grandpa: move error code to const

* grandpa: remove unnecessary WIP comment

* grandpa: remove Id type parameter for SharedVoterState

* grandpa: update tests to add shared_voter_state in parameters

* grandpa: remove old deprecated test

* grandpa: fix getting the correct set_id

* grandpa: make SharedVoterState a struct

* grandpa: wrap shared_voter_state in rpc_setup

* grandpa: replace spaces with tabs

* grandpa: limit RwLock write attempt to 1 sec

* grandpa: add missing doc comments and remove some pub

* Apply suggestions from code review

Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com>
Co-Authored-By: Hernando Castano <HCastano@users.noreply.github.com>

* grandpa: update function name call after change in finality-grandpa

* grandpa: group pub use and only export voter::report

* grandpa: add missing docs

* grandpa: extract out structs used for json serialization

* grandpa: stick to u32 for fields intended for js

* grandpa: move Error type to its own file

* grandpa: group pub use better

* Apply code review suggestion

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* grandpa: use correct version of finality-granpda in rpc crate

* grandpa: add back basic rpc unit test

* grandpa: replace SharedVoterState::new() with empty()

* node: cleanup grandpa::SharedVoterState usage in macro

* grandpa: remove VoterState error variant

* grandpa: enable missing futures compat feature

* grandpa: fix typo in error variant

* grandpa: remove test_utils

* grandpa: allow mocking rpc handler components

* grandpa: rename serialized to report in rpc module

* grandpa: add proper test for RPC

* grandpa: update to finality-grandpa v0.12.1

Co-authored-by: André Silva <andre.beat@gmail.com>
Co-authored-by: Demi Obenour <demi@parity.io>
Co-authored-by: Tomasz Drwięga <tomusdrw@users.noreply.github.com>
Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

substrate/Cargo.lock

@@ -1352,9 +1352,9 @@ dependencies = [
 
 [[package]]
 name = "finality-grandpa"
-version = "0.12.0"
+version = "0.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9d7907cc24468e29b5d3ea2097e78104492b6650c55f96af1f14e7915dc155ad"
+checksum = "5ab32971efbe776e46bfbc34d5b662d8e1de51fd14e26a2eba522c0f3470fc0f"
 dependencies = [
  "either",
  "futures 0.3.4",
@@ -3447,6 +3447,7 @@ dependencies = [
  "pallet-timestamp",
  "pallet-transaction-payment",
  "parity-scale-codec",
+ "parking_lot 0.10.2",
  "platforms",
  "rand 0.7.3",
  "regex",
@@ -3565,6 +3566,8 @@ dependencies = [
  "sc-consensus-babe",
  "sc-consensus-babe-rpc",
  "sc-consensus-epochs",
+ "sc-finality-grandpa",
+ "sc-finality-grandpa-rpc",
  "sc-keystore",
  "sp-api",
  "sp-blockchain",
@@ -3660,6 +3663,7 @@ dependencies = [
  "futures 0.3.4",
  "log",
  "node-template-runtime",
+ "parking_lot 0.10.2",
  "sc-basic-authorship",
  "sc-cli",
  "sc-client-api",
@@ -6400,6 +6404,23 @@ dependencies = [
  "tokio 0.2.18",
 ]
 
+[[package]]
+name = "sc-finality-grandpa-rpc"
+version = "0.8.0-dev"
+dependencies = [
+ "derive_more",
+ "finality-grandpa",
+ "futures 0.3.4",
+ "jsonrpc-core",
+ "jsonrpc-core-client",
+ "jsonrpc-derive",
+ "log",
+ "sc-finality-grandpa",
+ "serde",
+ "serde_json",
+ "sp-core",
+]
+
 [[package]]
 name = "sc-informant"
 version = "0.8.0-dev"