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>