Kill the light client, CHTs and change tries. (#10080)

* Remove light client, change tries and CHTs

* Update tests

* fmt

* Restore changes_root

* Fixed benches

* Cargo fmt

* fmt

* fmt

substrate/client/network/src/config.rs

@@ -23,7 +23,6 @@
 
 pub use crate::{
 	chain::Client,
-	on_demand_layer::{AlwaysBadChecker, OnDemand},
 	request_responses::{
 		IncomingRequest, OutgoingResponse, ProtocolConfig as RequestResponseConfig,
 	},
@@ -83,11 +82,6 @@ pub struct Params<B: BlockT, H: ExHashT> {
 	/// Client that contains the blockchain.
 	pub chain: Arc<dyn Client<B>>,
 
-	/// The `OnDemand` object acts as a "receiver" for block data requests from the client.
-	/// If `Some`, the network worker will process these requests and answer them.
-	/// Normally used only for light clients.
-	pub on_demand: Option<Arc<OnDemand<B>>>,
-
 	/// Pool of transactions.
 	///
 	/// The network worker will fetch transactions from this object in order to propagate them on