Moves all test runtimes to use derive_impl (#2409)

Step in https://github.com/paritytech/polkadot-sdk/issues/171

This PR adds `derive_impl` on all `frame_system` config impls for mock
runtimes. The overridden configs are maintained as of now to ensure
minimal changes.

---------

Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

substrate/frame/staking/src/mock.rs

@@ -23,7 +23,7 @@ use frame_election_provider_support::{
 	onchain, SequentialPhragmen, VoteWeight,
 };
 use frame_support::{
-	assert_ok, ord_parameter_types, parameter_types,
+	assert_ok, derive_impl, ord_parameter_types, parameter_types,
 	traits::{
 		ConstU64, Currency, EitherOfDiverse, FindAuthor, Get, Hooks, Imbalance, OnUnbalanced,
 		OneSessionHandler,
@@ -124,6 +124,7 @@ parameter_types! {
 	pub static Offset: BlockNumber = 0;
 }
 
+#[derive_impl(frame_system::config_preludes::TestDefaultConfig as frame_system::DefaultConfig)]
 impl frame_system::Config for Test {
 	type BaseCallFilter = frame_support::traits::Everything;
 	type BlockWeights = ();