Full block import benchmark (#4865)

* full block import benchmark

* try rocksdb cache

* add profiling helper

* use random keyring instead of zero caching

* update docs

* add more io stats

* remove last sentence

* add ci job to see

* Update primitives/keyring/src/sr25519.rs

Co-Authored-By: Marcio Diaz <marcio.diaz@gmail.com>

* switch to 100tx-block

* remove ci script

Co-authored-by: Marcio Diaz <marcio@parity.io>

substrate/client/db/src/lib.rs

@@ -1472,6 +1472,7 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 				average_transaction_size: io_stats.avg_transaction_size() as u64,
 				state_reads: state_stats.reads.ops,
 				state_reads_cache: state_stats.cache_reads.ops,
+				state_writes: state_stats.writes.ops,
 			},
 		})
 	}