Adds cli interface to allow reseting chain to a particular block (#9782)

* added BlockChainReset trait, client impl, and cli interface

* show block hashes to be deleted and new best block, update best block in db, better cli interface

* delete BlockNumber from COL_EXTRA

* add TODO comment

* add BlockReciepts to imports

* refactor block_headers_from_best_block, better cli documentation

* exit gracefully if reset arg isn't supplied

* fix cli usage macro

* removed stray int literals

* use Vec::with_capacity

Co-Authored-By: seunlanlege <seunlanlege@gmail.com>

* cast n to usize

* correct imports

* make db reset arg required

parity/configuration.rs

@@ -48,7 +48,7 @@ use ethcore_private_tx::{ProviderConfig, EncryptorConfig};
 use secretstore::{NodeSecretKey, Configuration as SecretStoreConfiguration, ContractAddress as SecretStoreContractAddress};
 use updater::{UpdatePolicy, UpdateFilter, ReleaseTrack};
 use run::RunCmd;
-use blockchain::{BlockchainCmd, ImportBlockchain, ExportBlockchain, KillBlockchain, ExportState, DataFormat};
+use blockchain::{BlockchainCmd, ImportBlockchain, ExportBlockchain, KillBlockchain, ExportState, DataFormat, ResetBlockchain};
 use export_hardcoded_sync::ExportHsyncCmd;
 use presale::ImportWallet;
 use account::{AccountCmd, NewAccount, ListAccounts, ImportAccounts, ImportFromGethAccounts};
@@ -176,6 +176,19 @@ impl Configuration {
 			}
 		} else if self.args.cmd_tools && self.args.cmd_tools_hash {
 			Cmd::Hash(self.args.arg_tools_hash_file)
+		} else if self.args.cmd_db && self.args.cmd_db_reset {
+			Cmd::Blockchain(BlockchainCmd::Reset(ResetBlockchain {
+				dirs,
+				spec,
+				pruning,
+				pruning_history,
+				pruning_memory: self.args.arg_pruning_memory,
+				tracing,
+				fat_db,
+				compaction,
+				cache_config,
+				num: self.args.arg_db_reset_num,
+			}))
 		} else if self.args.cmd_db && self.args.cmd_db_kill {
 			Cmd::Blockchain(BlockchainCmd::Kill(KillBlockchain {
 				spec: spec,