grandpa: round catchup messages (#2801)

* grandpa: initial structure for catch up messages

* grandpa: answer catch up requests

* grandpa: inject catch up messages into global stream

* grandpa: keep track of pending catch up request

* grandpa: block catchup until all referenced blocks are imported

* grandpa: unify catch up and commit streams

* grandpa: simplify communication stream/sink types

* grandpa: note gossip validator on catch up message import

* grandpa: fix cost on catch up message validation

* grandpa: check signatures on catch up messages

* grandpa: clean up catch up request handling state

* grandpa: adjust costs on invalid catch up requests

* grandpa: release lock before pushing catch up message

* grandpa: validate catch up request against peer view

* grandpa: catch up docs

* grandpa: fix tests

* grandpa: until_imported: add tests for catch up messages

* grandpa: add tests for catch up message gossip validation

* grandpa: integrate HistoricalVotes changes

* grandpa: add test for neighbor packet triggering catch up

* grandpa: add test for full voter catch up

* grandpa: depend on finality-grandpa 0.8 from crates

* granda: use finality-grandpa test helpers

* grandpa: add PSM cost for answering catch up requests

* grandpa: code style fixes

Co-Authored-By: Robert Habermeier <rphmeier@gmail.com>

* grandpa: more trailing commas

* grandpa: lower cost of invalid catch up requests near set change

* grandpa: process catch up sending on import of neighbor message

* grandpa: add comments on HistoricalVotes

* grandpa: use finality-grandpa v0.8.1 from crates.io

* grandpa: fix test compilation

substrate/Cargo.lock

@@ -861,8 +861,8 @@ dependencies = [
 
 [[package]]
 name = "finality-grandpa"
-version = "0.8.0"
-source = "git+https://github.com/paritytech/finality-grandpa?rev=f682e3dec54b19c5dd018324028c47f777f3b3a1#f682e3dec54b19c5dd018324028c47f777f3b3a1"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "hashmap_core 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4361,7 +4361,7 @@ name = "substrate-finality-grandpa"
 version = "2.0.0"
 dependencies = [
  "env_logger 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "finality-grandpa 0.8.0 (git+https://github.com/paritytech/finality-grandpa?rev=f682e3dec54b19c5dd018324028c47f777f3b3a1)",
+ "finality-grandpa 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "fork-tree 2.0.0",
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5912,7 +5912,7 @@ dependencies = [
 "checksum failure_derive 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "ea1063915fd7ef4309e222a5a07cf9c319fb9c7836b1f89b85458672dbb127e1"
 "checksum fake-simd 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e88a8acf291dafb59c2d96e8f59828f3838bb1a70398823ade51a84de6a6deed"
 "checksum fdlimit 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b1ee15a7050e5580b3712877157068ea713b245b080ff302ae2ca973cfcd9baa"
-"checksum finality-grandpa 0.8.0 (git+https://github.com/paritytech/finality-grandpa?rev=f682e3dec54b19c5dd018324028c47f777f3b3a1)" = "<none>"
+"checksum finality-grandpa 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b9e7cba2aaadf09932452a4fc054a77451b31eb99bc0b42bf54bd44f01a9daf4"
 "checksum fixed-hash 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "516877b7b9a1cc2d0293cbce23cd6203f0edbfd4090e6ca4489fecb5aa73050e"
 "checksum flate2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)" = "550934ad4808d5d39365e5d61727309bf18b3b02c6c56b729cb92e7dd84bc3d8"
 "checksum fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)" = "2fad85553e09a6f881f739c29f0b00b0f01357c743266d478b68951ce23285f3"