* Added MSET command
MSET command added. Requires all keys to have the same JSON Path, which might fit most use cases, but is a limitation. Optionally we could make the path an array as well to support all use cases.
* change JSON.MSET signature, add to json command object, fix tests
* its `item.value`, not `item.json`..
* Update MSET.ts
Removed unused RedisCommandArguments
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Co-authored-by: Leibale Eidelman <me@leibale.com>