Add support for redis namespaces

[Demannu]

Why?

I'm exploring running screeps in a distributed way and separating each instance while maintain a cluster deployed redis is super useful. I had made this fork for myself to enable prefixing the redis queries and it's worked fairly well. I thought I'd share it with the community

How?

Add a new dependency ioredis which has native Redis client class support while also adding some optimization and most importantly key prefixing

This allows a drop-in replacement which also honors a new configuration option namespace which is then translated to ${namespace}: and saved to redis.config.keyPrefix. The remaining calls are natively compatible and had no known issues.

[AlinaNova21]

This seems like an interesting idea, my only concern is it is a breaking change, as if I'm understanding this correctly, it will require a reset and not work with current databases. Would there be an easy change to allow existing databases to work? Maybe default namespace to ""?

[Demannu]

It would be a breaking change, you're correct. I hadn't considered that.

Defaulting to an empty string should work 👍

[AlinaNova21]

Was just looking into it a bit more, it seems that this wouldn't be safe to use, ioredis does not do any rewriting to work around calls such as flushdb, meaning everytime a resetAllData is called, or even importMap, it would result in clearing the enttire redis instance. Not just the prefixes. I found a few issues mentioning this along with a warning in the readme.
redis/ioredis#239 (comment)
redis/ioredis#325 (comment)

An alternative, which I have actually used in the past, is pass in the db number to redis. Which screepsmod-mongo already supports via config.redis.database or by passing a redis url containing one.