Do not use Option to wrap GenesisConfig fields (#8275)

Currently we wrap every `GenesisConfig` field in an `Option`, while
we require `Default` being implemented for all pallet genesisconfigs.
Passing `None` also results in the genesis not being initialized, which
is a bug as seen from the perspective of a pallet developer?

This pr changes the fields of the `GenesisConfig` to non `Option` types.

substrate/bin/node-template/node/src/chain_spec.rs

@@ -134,24 +134,24 @@ fn testnet_genesis(
 	_enable_println: bool,
 ) -> GenesisConfig {
 	GenesisConfig {
-		frame_system: Some(SystemConfig {
+		frame_system: SystemConfig {
 			// Add Wasm runtime to storage.
 			code: wasm_binary.to_vec(),
 			changes_trie_config: Default::default(),
-		}),
-		pallet_balances: Some(BalancesConfig {
+		},
+		pallet_balances: BalancesConfig {
 			// Configure endowed accounts with initial balance of 1 << 60.
 			balances: endowed_accounts.iter().cloned().map(|k|(k, 1 << 60)).collect(),
-		}),
-		pallet_aura: Some(AuraConfig {
+		},
+		pallet_aura: AuraConfig {
 			authorities: initial_authorities.iter().map(|x| (x.0.clone())).collect(),
-		}),
-		pallet_grandpa: Some(GrandpaConfig {
+		},
+		pallet_grandpa: GrandpaConfig {
 			authorities: initial_authorities.iter().map(|x| (x.1.clone(), 1)).collect(),
-		}),
-		pallet_sudo: Some(SudoConfig {
+		},
+		pallet_sudo: SudoConfig {
 			// Assign network admin rights.
 			key: root_key,
-		}),
+		},
 	}
 }