include _airbyte_loaded_at or similar in final tables

[bmulh]

We often have syncs that run for an extended period. The _airbyte_extracted_at can be a day or two in the past by the time the data is finally insert into the destination table. This causes problems for our data pipeline if it is ran during a sync as we can miss records. We would like to know when the data landed in the final table, it'd be helpful if the _airbyte_loaded_at or a similar column was included in the final destination schema that is set to the current timestamp when the record is insert.

We currently use the postgres destination but this could be helpful across other database destinations.

edit: What we really need is the concept of "originally loaded at" since when the final table is rebuilt, we want to persist the original loaded at concept. Essentially the same concept of the _airbyte_loaded_at in the raw table