Implement the updated Postgres 17 Merge+Returning feature for Postgres Destinations to allow for an Incremental + Merged Strategy

[walker-philips]

The changes to Merge Returning in Postgres 17 could allow for an optimized merge strategy that handles inserts, updates, and deletes on records. As of now, data transferred into Postgres via incremental ensures an SCD-esque dataset which is suboptimal in certain circumstances as total parity between the source and destination is lost. By introducing a changing dimension, the Postgres Destination is almost certainly required to perform additional transformations to eliminate duplications as well as delete/inactivate rows no longer present in the source.