Feature Request: Configurable partitioning for BigQuery exports

Feature request

Is your feature request related to a problem?

Allow the granularity of timestamp partitioning for BigQuery exports to be configured, to help improve query performance.

Additional context

From: https://posthoghelp.zendesk.com/agent/tickets/27037 (moved to PostHog: https://us.posthog.com/project/2/support/tickets/28726)

Seems we have a TODO to look at making partitioning configurable: https://github.com/PostHog/posthog/blob/78f4374769d53ddccc9a7eacb893fefe473c96a1/posthog/temporal/batch_exports/bigquery_batch_export.py#L186-L190

Debug info

Kind: support

Target area: apps

Report event: http://go/ticketByUUID/9e253d84-c05b-4000-8a7b-3b82f4cc84cf

Session: https://us.posthog.com/project/sTMFPsFhdP1Ssg/replay/019590f9-6cc4-7e16-ad7b-89ab97602c49?t=46

Exceptions: https://us.posthog.com/project/2/error_tracking?filterGroup=%7B%22type%22%3A%22AND%22%2C%22values%22%3A%5B%7B%22type%22%3A%22AND%22%2C%22values%22%3A%5B%7B%22key%22%3A%22%24session_id%22%2C%22value%22%3A%5B%22019590f9-6cc4-7e16-ad7b-89ab97602c49%22%5D%2C%22operator%22%3A%22exact%22%2C%22type%22%3A%22event%22%7D%5D%7D%5D%7D

Location: https://us.posthog.com/project/65144

Sentry: http://go/sentryUS/65144

Persons-on-events mode for project: person_id_override_properties_joined

Start in posthog/temporal/batch_exports/bigquery_batch_export.py around lines 186-190, where the TODO about configurable partitioning is noted. Trace how BigQuery export settings are represented and passed into the exporter, then determine the supported timestamp partitioning options. Done means the partitioning granularity can be configured for BigQuery exports and the resulting export behavior is covered by the relevant tests, if present.