cmd, eth, miner: make recommit configurable (#17444)

* cmd, eth, miner: make recommit configurable

* cmd, eth, les, miner: polish a bit

* miner: filter duplicate sealing work

* cmd: remove uncessary conversion

* miner: avoid microptimization in favor of cleaner code

internal/web3ext/web3ext.go

@@ -519,6 +519,11 @@ web3._extend({
 			params: 1,
 			inputFormatter: [web3._extend.utils.fromDecimal]
 		}),
+		new web3._extend.Method({
+			name: 'setRecommitInterval',
+			call: 'miner_setRecommitInterval',
+			params: 1,
+		}),
 		new web3._extend.Method({
 			name: 'getHashrate',
 			call: 'miner_getHashrate'