feature(Druid) Support export buckets

[pauldheinrichs]

As of druid v29 - you can now write to an external location

• https://github.com/apache/druid/releases#29.0.0-important-features%2C-changes%2C-and-deprecations-msq-export-statements-%28experimental%29

I imagine i'd be slightly more performant for druid to utilize this where applicable.

Related docs:

• https://druid.apache.org/docs/latest/multi-stage-query/reference/#extern-function

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