feat: New ingestion consumer

[benjackwhite]

Problem

This PR is the first in a few steps to start refactoring the plugin server to be much cleaner and more minimal

Changes

• New consumer based of the same class based consumer for cdp
• Essentially does the same thing as the old each-batch-ingestion process but cleaner and removing a lot of complex code paths
• Changes to be much more config driven - this allows us to run multiple version of exactly the same consumer just with different source / destination topics and consumer group IDs
• Adds a new mode for local running (not default) so that we can test all ingestion consumers this way - this will become the default once we release and remove the older options
• Tests to cover most of this

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Does this work well for both Cloud and self-hosted?

How did you test this code?