Remove uncles related code (#13216)

The code was added without any clear usage. The inherent for example is not benchmarked and not used.

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

@@ -488,14 +488,8 @@ impl pallet_timestamp::Config for Runtime {
 	type WeightInfo = pallet_timestamp::weights::SubstrateWeight<Runtime>;
 }
 
-parameter_types! {
-	pub const UncleGenerations: BlockNumber = 5;
-}
-
 impl pallet_authorship::Config for Runtime {
 	type FindAuthor = pallet_session::FindAccountFromAuthorIndex<Self, Babe>;
-	type UncleGenerations = UncleGenerations;
-	type FilterUncle = ();
 	type EventHandler = (Staking, ImOnline);
 }