chain-spec: getting ready for native-runtime-free world (#1256)

This PR prepares chains specs for _native-runtime-free_  world.

This PR has following changes:
- `substrate`:
  - adds support for:
- JSON based `GenesisConfig` to `ChainSpec` allowing interaction with
runtime `GenesisBuilder` API.
- interacting with arbitrary runtime wasm blob to[
`chain-spec-builder`](https://github.com/paritytech/substrate/blob/3ef576eaeb3f42610e85daecc464961cf1295570/bin/utils/chain-spec-builder/src/lib.rs#L46)
command line util,
- removes
[`code`](https://github.com/paritytech/substrate/blob/3ef576eaeb3f42610e85daecc464961cf1295570/frame/system/src/lib.rs#L660)
from `system_pallet`
  - adds `code` to the `ChainSpec`
- deprecates
[`ChainSpec::from_genesis`](https://github.com/paritytech/substrate/blob/3ef576eaeb3f42610e85daecc464961cf1295570/client/chain-spec/src/chain_spec.rs#L263),
but also changes the signature of this method extending it with `code`
argument.
[`ChainSpec::builder()`](https://github.com/paritytech/substrate/blob/20bee680ed098be7239cf7a6b804cd4de267983e/client/chain-spec/src/chain_spec.rs#L507)
should be used instead.
- `polkadot`:
- all references to `RuntimeGenesisConfig` in `node/service` are
removed,
- all
`(kusama|polkadot|versi|rococo|wococo)_(staging|dev)_genesis_config`
functions now return the JSON patch for default runtime `GenesisConfig`,
  - `ChainSpecBuilder` is used, `ChainSpec::from_genesis` is removed,

- `cumulus`:
  - `ChainSpecBuilder` is used, `ChainSpec::from_genesis` is removed,
- _JSON_ patch configuration used instead of `RuntimeGenesisConfig
struct` in all chain specs.
  
---------

Co-authored-by: command-bot <>
Co-authored-by: Javier Viola <javier@parity.io>
Co-authored-by: Davide Galassi <davxy@datawok.net>
Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>
Co-authored-by: Kevin Krone <kevin@parity.io>
Co-authored-by: Bastian Köcher <git@kchr.de>

substrate/bin/node/testing/src/genesis.rs

@@ -20,22 +20,21 @@
 
 use crate::keyring::*;
 use kitchensink_runtime::{
-	constants::currency::*, wasm_binary_unwrap, AccountId, AssetsConfig, BabeConfig,
-	BalancesConfig, GluttonConfig, GrandpaConfig, IndicesConfig, RuntimeGenesisConfig,
-	SessionConfig, SocietyConfig, StakerStatus, StakingConfig, SystemConfig,
-	BABE_GENESIS_EPOCH_CONFIG,
+	constants::currency::*, AccountId, AssetsConfig, BabeConfig, BalancesConfig, GluttonConfig,
+	GrandpaConfig, IndicesConfig, RuntimeGenesisConfig, SessionConfig, SocietyConfig, StakerStatus,
+	StakingConfig, BABE_GENESIS_EPOCH_CONFIG,
 };
 use sp_keyring::{Ed25519Keyring, Sr25519Keyring};
 use sp_runtime::Perbill;
 
 /// Create genesis runtime configuration for tests.
-pub fn config(code: Option<&[u8]>) -> RuntimeGenesisConfig {
-	config_endowed(code, Default::default())
+pub fn config() -> RuntimeGenesisConfig {
+	config_endowed(Default::default())
 }
 
 /// Create genesis runtime configuration for tests with some extra
 /// endowed accounts.
-pub fn config_endowed(code: Option<&[u8]>, extra_endowed: Vec<AccountId>) -> RuntimeGenesisConfig {
+pub fn config_endowed(extra_endowed: Vec<AccountId>) -> RuntimeGenesisConfig {
 	let mut endowed = vec![
 		(alice(), 111 * DOLLARS),
 		(bob(), 100 * DOLLARS),
@@ -48,10 +47,7 @@ pub fn config_endowed(code: Option<&[u8]>, extra_endowed: Vec<AccountId>) -> Run
 	endowed.extend(extra_endowed.into_iter().map(|endowed| (endowed, 100 * DOLLARS)));
 
 	RuntimeGenesisConfig {
-		system: SystemConfig {
-			code: code.map(|x| x.to_vec()).unwrap_or_else(|| wasm_binary_unwrap().to_vec()),
-			..Default::default()
-		},
+		system: Default::default(),
 		indices: IndicesConfig { indices: vec![] },
 		balances: BalancesConfig { balances: endowed },
 		session: SessionConfig {