Add bigint column and add data sync trigger to geo_event_log

What does this MR do and why?

As outlined in #433432 we want to change the column type for event ids. This MR is the first of 4 steps to do this. Here we only add a new bigint column and a trigger to copy data from geo_event_id to it. This also adds a backfill migration to sync the two columns.

Related issue: #433432

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