enable multiple chainhook nodes to share a redis store

[MicaiahReid]

It would be great for the Platform chainhook nodes to have some replication - two Chainhook nodes processing blocks and keeping up with the stacks/btc chains, but only one processing predicates and reading/writing from the redis store at a time.

Then, if one of the nodes has a problem handling a reorg or falls behind chaintip, we can swap out the active environment while still processing the same predicates.

See this comment for more details.