Minimal switch of substrate-node to GRANDPA /Aura (#1128)

* add beginnings of SRML grandpa library

* get srml-grandpa compiling

* tests for srml-grandpa

* add optional session integration to grandpa SRML

* start integration into node runtime

* Allow extracting pending change from header digest

* Make it compile on wasm

* make tests compile again

* Move Authority Key fetching into service, simplify service factory construction

* Generalize Authority Consensus Setup system

* Add Authority Setup Docs

* Allow CLI params to be extensible

 - move params to structopts
 - split parsing and default command execution
 - add custom config to node
 - extended parsing of custom config
 - extending params via structop's flatten

* Minor fixes on cli extension params:
 - added docs
 - re-add actual app name, rather than node-name
 - make strategy and subcommand optional

* better cli params

* synchronize GRANDPA and normal node authorities

* Implement grandpa::network for gossip consensus

* run_grandpa in Node

* Fix missed merge error

* Integrate grandpa import queue

* more specific type def

* link up linkhalf and import block

* make grandpa future send

* get compiling

* Fix new params convention and license header

* get it running

* rebuild node runtime WASM

* change logging level

* Update node/cli/src/params.rs

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

* Update node/cli/src/params.rs

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

* Update node/cli/src/lib.rs

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

* Update node/runtime/src/lib.rs

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

* Update node/cli/src/lib.rs

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

* Clean up and Fixme for mutable config

* Move GrandpaService Integration into grandpa, feature gated but on per default

* Fixing grandpa runtime module test

* Update wasm runtime hashes for tests

* GRANDPA: use post-header hash when logging scheduled changes

* add an extra bit of logging to authorities

* fixing missing constrain

* remove old code

* move `NewAuthorities` to an event in srml-grandpa

* fix node-executor tests to use grandpa log

* Remove GossipConsensus from tests, use newly provided sync-feature, fixes tests

* Update to latest wasm runtimes

* address grumbles

* address grumbles

* only derive deserialize when using std

* Clean up use of Deserialize

substrate/core/finality-grandpa/primitives/src/lib.rs

@@ -17,6 +17,10 @@
 //! Primitives for GRANDPA integration, suitable for WASM compilation.
 
 #![cfg_attr(not(feature = "std"), no_std)]
+#![cfg_attr(not(feature = "std"), feature(alloc))]
+
+#[cfg(not(feature = "std"))]
+extern crate alloc;
 
 extern crate substrate_primitives;
 extern crate sr_primitives;
@@ -57,6 +61,14 @@ pub mod id {
 	pub const GRANDPA_API: ApiId = *b"fgrandpa";
 }
 
+/// Well-known storage keys for GRANDPA.
+pub mod well_known_keys {
+	/// The key for the authorities and weights vector in storage.
+	pub const AUTHORITY_PREFIX: &[u8] = b":grandpa:auth:";
+	/// The key for the authorities count.
+	pub const AUTHORITY_COUNT: &[u8] = b":grandpa:auth:len";
+}
+
 decl_runtime_apis! {
 	/// APIs for integrating the GRANDPA finality gadget into runtimes.
 	/// This should be implemented on the runtime side.
@@ -76,6 +88,10 @@ decl_runtime_apis! {
 		///
 		/// No change should be scheduled if one is already and the delay has not
 		/// passed completely.
+		///
+		/// This should be a pure function: i.e. as long as the runtime can interpret
+		/// the digest type it should return the same result regardless of the current
+		/// state.
 		fn grandpa_pending_change(digest: DigestFor<Block>)
 			-> Option<ScheduledChange<NumberFor<Block>>>;