Define ss58 prefix inside the runtime (#7810)

* Add SS58Prefix type to the frame_system config trait

* Remove unused chain_id runtime interface

substrate/bin/node/runtime/src/lib.rs

@@ -176,6 +176,7 @@ parameter_types! {
 		})
 		.avg_block_initialization(AVERAGE_ON_INITIALIZE_RATIO)
 		.build_or_panic();
+	pub const SS58Prefix: u8 = 42;
 }
 
 const_assert!(NORMAL_DISPATCH_RATIO.deconstruct() >= AVERAGE_ON_INITIALIZE_RATIO.deconstruct());
@@ -202,6 +203,7 @@ impl frame_system::Config for Runtime {
 	type OnNewAccount = ();
 	type OnKilledAccount = ();
 	type SystemWeightInfo = frame_system::weights::SubstrateWeight<Runtime>;
+	type SS58Prefix = SS58Prefix;
 }
 
 impl pallet_utility::Config for Runtime {