grandpa: report equivocations (#3868)

* session: runtime api for generating session membership proofs

* grandpa: add runtime api for creating equivocation report txs

* grandpa: submit signed equivocation report transactions

* grandpa: use proper equivocation report type

* grandpa: report equivocations

* grandpa: validate equivocation proof

* grandpa: update to finality-grandpa 0.9.1

* grandpa: fix encoding of session membership proof

* grandpa: initialize set id session mapping for genesis session

* grandpa: fix bug in set_id session validation

* fix compilation

* cleanup from merge conflicts

* cleanup crate tomls

* grandpa: refactor equivocation handling to separate trait

* node-template: fix compilation

* fix test compilation

* bump finality-grandpa to v0.10.2

* rpc: fix runtime version test

* CHERRY-PICK #4200: Add documentation to SubmitSignedTransaction and actually make it work

Squashed commit of the following:

commit 4f2cb0b1c588a06f2f3b478bb4b28b5cb29d54b9
Author: Tomasz Drwięga <tomasz@parity.io>
Date:   Tue Dec 3 16:29:33 2019 +0100

    Split the method to avoid confusing type error message.

commit c5bf24eeaaf902add89ed1b046b22c4a4aaeb2cd
Author: Tomasz Drwięga <tomasz@parity.io>
Date:   Tue Dec 3 16:19:55 2019 +0100

    Make accounts optional, fix logic.

commit 97db1ef556e023cf6847e5ffdb036c0e3ea6fb0a
Author: Tomasz Drwięga <tomasz@parity.io>
Date:   Tue Dec 3 10:06:20 2019 +0100

    Remove warning.

commit 535f5c116d1a2e826eaf90c3f7e6798e443d61d8
Merge: 516257217 0f1a5f651
Author: Tomasz Drwięga <tomasz@parity.io>
Date:   Tue Dec 3 07:08:05 2019 +0100

    Merge branch 'master' into td-signed-transactions

commit 516257217bac89fcebd083712f4ea68b7b23b55a
Merge: ac98248c6 2e68c80c2
Author: Tomasz Drwięga <tomasz@parity.io>
Date:   Mon Dec 2 13:57:25 2019 +0100

    Merge branch 'master' into td-signed-transactions

commit ac98248c6c56cff381130645a82a13d29933cf83
Author: Tomasz Drwięga <tomasz@parity.io>
Date:   Mon Nov 25 17:34:52 2019 +0100

    Forgotten import.

commit 67a3c19031506c28e31c6bc4a90fff62d467dd58
Author: Tomasz Drwięga <tomasz@parity.io>
Date:   Mon Nov 25 17:32:10 2019 +0100

    Fix naming and bounds.

commit 93e768ea9df97a4629fca1f9bc4b108fdb33f876
Author: Tomasz Drwięga <tomasz@parity.io>
Date:   Mon Nov 25 17:01:05 2019 +0100

    Add documentation to signed transactions and actually make them work.

* grandpa: skip block initialization on report submission method

* primitives: allow transaction pool access by default for offchain calls

* grandpa: unused parameters

* grandpa: remove unused method

* grandpa: enable equivocation reporting

* grandpa: add workaround for parameter encoding

* grandpa: fix localized_payload calls in tests

* fix submit_report_equivocation_extrinsic in runtimes

* node: fix submit transaction test compilation

* node: bump spec_version

* rpc: fix api version test

* grandpa: allow custom equivocation offence type

* grandpa: add test for authorities::next_change_height

* grandpa: cleanup report_equivocation function

* node: move reporting app crypto to node-primitives

* grandpa: move equivocation traits to own module

* grandpa: rename app-crypto crate import

* grandpa: export equivocation types

* node: bump spec_version

* grandpa: rename EquivocationReport to EquivocationProof

* grandpa: add missing docs to primitives

* grandpa: add missing docs to equivocation

* node: fix compilation

* grandpa: add missing docs to pallet

* node: bump spec_version

* fix whitespace

* grandpa: return error on offence reporting

* grandpa: expose session and validator count in proofs through traits

* grandpa: use strong key in module KeyOwnerProofSystem

* grandpa: move key ownership proof to grandpa runtime api

* grandpa: remove unnecessary cloning when checking equivocation proof

* grandpa: make report_equivocation a method in Environment

* support: implement KeyOwnerProofSystem for ()

* grandpa: move KeyOwnerProofSystem to module trait

* test-utils: fix runtime compilation

* grandpa: fix test compilation

* grandpa: fix test compilation after merge

* grandpa: simplify transaction submission types

* grandpa: validate equivocation report in signed extension

* client: fix test

* node: use ValidateEquivocationReport signed extension

* grandpa: expose key ownership proof under opaque type

* grandpa: better docs on key ownership proofs

* grandpa: add note about signed extension

* grandpa: add ValidateEquivocationReport::new

* grandpa: remove skip_initialize_block from runtime api

* grandpa: use new offchain transaction submission API

* grandpa: take set_id in generate_key_ownership_proof

* grandpa: update to finality-grandpa v0.12.2

* grandpa: cleanup usages of AuthoritySet::current

* grandpa: fix test

* grandpa: add mocking utilities for equivocation reporting

* grandpa: add test for equivocation reporting

* grandpa: move SetIdSession initialization

* grandpa: add more tests

* node: enable historical session manager

* node: bump spec_version

* node: use strong key types in KeyOwnerProofSystem definitions

* grandpa: export GrandpaEquivocationOffence type

substrate/Cargo.lock

@@ -1352,9 +1352,9 @@ dependencies = [
 
 [[package]]
 name = "finality-grandpa"
-version = "0.12.1"
+version = "0.12.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5ab32971efbe776e46bfbc34d5b662d8e1de51fd14e26a2eba522c0f3470fc0f"
+checksum = "1f4682570188cd105606e621b9992e580f717c15f8cd1b7d106b59f1c6e54680"
 dependencies = [
  "either",
  "futures 0.3.4",
@@ -3440,6 +3440,7 @@ dependencies = [
  "pallet-authority-discovery",
  "pallet-balances",
  "pallet-contracts",
+ "pallet-grandpa",
  "pallet-im-online",
  "pallet-indices",
  "pallet-staking",
@@ -3546,7 +3547,10 @@ dependencies = [
 name = "node-primitives"
 version = "2.0.0-dev"
 dependencies = [
+ "frame-system",
+ "parity-scale-codec",
  "pretty_assertions",
+ "sp-application-crypto",
  "sp-core",
  "sp-runtime",
  "sp-serializer",
@@ -4275,16 +4279,25 @@ dependencies = [
 name = "pallet-grandpa"
 version = "2.0.0-dev"
 dependencies = [
+ "finality-grandpa",
  "frame-support",
  "frame-system",
+ "pallet-balances",
  "pallet-finality-tracker",
+ "pallet-offences",
  "pallet-session",
+ "pallet-staking",
+ "pallet-staking-reward-curve",
+ "pallet-timestamp",
  "parity-scale-codec",
  "serde",
+ "sp-application-crypto",
  "sp-core",
  "sp-finality-grandpa",
  "sp-io",
+ "sp-keyring",
  "sp-runtime",
+ "sp-session",
  "sp-staking",
  "sp-std",
 ]
@@ -4486,6 +4499,7 @@ dependencies = [
  "sp-core",
  "sp-io",
  "sp-runtime",
+ "sp-session",
  "sp-staking",
  "sp-std",
  "sp-trie",
@@ -7524,10 +7538,13 @@ dependencies = [
 name = "sp-finality-grandpa"
 version = "2.0.0-dev"
 dependencies = [
+ "finality-grandpa",
+ "log",
  "parity-scale-codec",
  "serde",
  "sp-api",
  "sp-application-crypto",
+ "sp-core",
  "sp-runtime",
  "sp-std",
 ]
@@ -7760,9 +7777,11 @@ dependencies = [
 name = "sp-session"
 version = "2.0.0-dev"
 dependencies = [
+ "parity-scale-codec",
  "sp-api",
  "sp-core",
  "sp-runtime",
+ "sp-staking",
  "sp-std",
 ]
 
@@ -8027,6 +8046,7 @@ dependencies = [
  "node-primitives",
  "node-runtime",
  "pallet-balances",
+ "pallet-grandpa",
  "pallet-transaction-payment",
  "parity-scale-codec",
  "rand 0.7.3",
@@ -8181,6 +8201,7 @@ dependencies = [
  "sp-consensus-aura",
  "sp-consensus-babe",
  "sp-core",
+ "sp-finality-grandpa",
  "sp-inherents",
  "sp-io",
  "sp-keyring",