redis cluster support

[splitice]

This version will actually work against redis cluster (and non redis cluster).

Validated against a keydb based cluster CI environment and a redis-server standalone.

Key changes include:

• consistent key prefixing with {}
• Use of RedisKey in lua script generation to ensure the correct server receives the EVAL

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[ejsmith]

@splitice Thank you! I seem to recall there were other issues trying to make use of Redis cluster. Did you test the library pretty extensively on Redis cluster? Also, I forget if we test against both cluster and single server in our tests, but it would be good to test against both if this is fixing cluster issues.

[splitice]

@ejsmith My testing is limited to RedisQueue, thats the only component we need at this time