Support CLUSTER commands (#2015)

* Support CLUSTER commands

* add some client tests

* remove only

* delete cluster slaves

* delete reset clietn test

* SET SLOT

* test with client

* fix fail

* Update CLUSTER_COUNTKEYSINSLOT.spec.ts

* move commands to client/commands.ts

* clusterNode

* remove CLUSTER-SET-CONFIG-EPOCH test with client

* clean code

Co-authored-by: leibale <leibale1998@gmail.com>

packages/client/lib/commands/CLUSTER_SAVECONFIG.spec.ts

@@ -0,0 +1,19 @@
+import { strict as assert } from 'assert';
+import testUtils, { GLOBAL } from '../test-utils';
+import { transformArguments } from './CLUSTER_SAVECONFIG';
+
+describe('CLUSTER SAVECONFIG', () => {
+    it('transformArguments', () => {
+        assert.deepEqual(
+            transformArguments(),
+            ['CLUSTER', 'SAVECONFIG']
+        );
+    });
+
+    testUtils.testWithCluster('clusterNode.clusterSaveConfig', async cluster => {
+        assert.equal(
+            await cluster.getSlotMaster(0).client.clusterSaveConfig(),
+            'OK'
+        );
+    }, GLOBAL.CLUSTERS.OPEN);
+});