14230: postgres metadata calculations

[kimerinn]

What

Postgres metadata calculations added to Postgres source

🚨 User Impact 🚨

Are there any breaking changes? What is the end result perceived by the user? If yes, please merge this PR with the 🚨🚨 emoji so changelog authors can further highlight this if needed.

Pre-merge Checklist

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New Connector

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Updating a connector

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Tests

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