retryStrategy doesn't work properly

According to ioredis JS [spec](https://github.com/luin/ioredis), to disable reconnecting you need to pass anything that is not a number. But the `retryStrategy` option in PureScript does not support this "not a number" result because it returns `Int`. Hopefully, it's possible to return `unsafeCoerce "dummy"` to the `retryStrategy` option, and it will raise exception and stop reconnecting on evaluation. However it's not a valid way I think. It would be better to allow the `retryStrategy` option to have another type: `SimpleConOpts -> Maybe Int` and convert this `Maybe` before passing to JS function.

Start from the retryStrategy option and the SimpleConOpts definition, then inspect how the PureScript option is converted for ioredis. Verify that a Maybe Int can represent both a retry delay and disabled reconnecting, and test both outcomes against the ioredis behavior described in the issue.

Written by the indexing model from the issue text.