fix #1970 - add support for RESTORE (#2535)

* - Added RESTORE functionality

* add FIRST_KEY_INDEX, fix tests, clean example, add example to examples table

* use returnBuffers in test

---------

Co-authored-by: Leibale Eidelman <me@leibale.com>

examples/dump-and-restore.js

@@ -0,0 +1,22 @@
+// This example demonstrates the use of the DUMP and RESTORE commands
+
+import { commandOptions, createClient } from 'redis';
+
+const client = createClient();
+await client.connect();
+
+// DUMP a specific key into a local variable
+const dump = await client.dump(
+    commandOptions({ returnBuffers: true }),
+    'source'
+);
+
+// RESTORE into a new key
+await client.restore('destination', 0, dump);
+
+// RESTORE and REPLACE an existing key
+await client.restore('destination', 0, dump, {
+    REPLACE: true
+});
+
+await client.quit();