Recommend Node-Redis for new projects, clarify that ioredis will continue to be maintained.

[mcohen75]

Based on discussion in https://github.com/redis/ioredis/issues/1870 it seems that Node-Redis should be used when in search of a Node.js client for Redis on a new project. The community would benefit from knowing this, which is why I'd suggest making this prominent as I have here.

[kristianjaeger]

Thanks for proposing this. I'm not sure why the Redis org has not commented / approved?? Cheers.