Deprecate old approach for argument encoding, with faster alternative

[rscarson]

Arguments used to be encoded as an array ref of serde_json::Value, which was inefficient
Now, function calls accept a single &impl Serialize argument, which is decoded directly by v8

The old macro is left in place for compatibility, and a new big_json_args is now available that uses the old method to bypass serde's 16 arg tuple limit.