[Feature] Add support for snapshot hard deletes in spark/databricks

[colin-rogers-dbt]

Is this your first time submitting a feature request?

• I have read the expectations for open source contributors
• I have searched the existing issues, and I could not find an existing issue for this feature
• I am requesting a straightforward extension of existing dbt functionality, rather than a Big Idea better suited to a discussion

Describe the feature

Tests defined here should pass: #1378

We never properly added support for snapshot hard deletes (and probably other snapshot variations as well) in dbt-spark. This is blocking dbt-databricks as it inherits from spark.

Describe alternatives you've considered

No response

Who will this benefit?

No response

Are you interested in contributing this feature?

No response

Anything else?

No response

[JERRY-OLD-KINGFISHER]

Hi guys, it is really important for us to make this fix. We are using a scd2 snapshots with tracking deletions (hard_deletes : new_record), so that method is critical for us to cover a design requirements.
Thank you.