Keep Kafka tables in sync

[macobo]

Proposed change

bin/migrate should check Kafka engine tables and if the desired schema has change update the tables.

Filing this here as it's most relevant for self-hosted users.

Alternative options

Document how to manually, but this is tricky.

Additional context

This came up testing #279 - if kafka host ever changes, posthog would never pick this up.

Related pain point here is protobuf though: PostHog/posthog#8334

[hazzadous]

Related issue mentioned in this community support slack thread

This fits under the case:

if kafka host ever changes, posthog would never pick this up

and also offers some useful insights into specifying the broker hosts via kafka/metadata_broker_list on the operator, which would allow us to specify on a cluster level which kafka to use.