[DEV-15225] Fix postgres db name and recreation

[ltellesfl]

Note

Medium Risk
Changes Crunchy Postgres instance-set naming and anti-affinity selectors, which can affect pod scheduling and potentially trigger database pod replacement if labels no longer match existing resources.

Overview
Adjusts the generated Crunchy Postgres instances config to target the correct cluster label (postgres-data instead of postgres-insights) in pod anti-affinity rules.

Also parameterizes the instance set name via new crunchy_instance_name (default pgha1), updating the anti-affinity instance-set match and instance name to avoid hard-coded values and reduce unintended instance recreation across environments.

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[NathanOkolita]

Looks good.