cmd, core, params: add support for the Holesky testnet (#28007)

* cmd, core, params: add support for the Holesky testnet

* cmd/devp2p: add support for holesky for the dns crawler

cmd/geth/main.go

@@ -275,6 +275,9 @@ func prepare(ctx *cli.Context) {
 	case ctx.IsSet(utils.SepoliaFlag.Name):
 		log.Info("Starting Geth on Sepolia testnet...")
 
+	case ctx.IsSet(utils.HoleskyFlag.Name):
+		log.Info("Starting Geth on Holesky testnet...")
+
 	case ctx.IsSet(utils.DeveloperFlag.Name):
 		log.Info("Starting Geth in ephemeral dev mode...")
 		log.Warn(`You are running Geth in --dev mode. Please note the following:
@@ -299,7 +302,8 @@ func prepare(ctx *cli.Context) {
 	// If we're a full node on mainnet without --cache specified, bump default cache allowance
 	if ctx.String(utils.SyncModeFlag.Name) != "light" && !ctx.IsSet(utils.CacheFlag.Name) && !ctx.IsSet(utils.NetworkIdFlag.Name) {
 		// Make sure we're not on any supported preconfigured testnet either
-		if !ctx.IsSet(utils.SepoliaFlag.Name) &&
+		if !ctx.IsSet(utils.HoleskyFlag.Name) &&
+			!ctx.IsSet(utils.SepoliaFlag.Name) &&
 			!ctx.IsSet(utils.GoerliFlag.Name) &&
 			!ctx.IsSet(utils.DeveloperFlag.Name) {
 			// Nope, we're really on mainnet. Bump that cache up!