1. Proposed title of this feature request
Support PostgreSQL trigger for KEDA in Custom Metrics Autoscaler

2. What is the nature and description of the request?

 
The customer uses PostgreSQL and other applications that leverage PostgreSQL as as BD (like airflow) as it provides a standard database solution across platforms for them. Scaling on apps/pods based on data stored in PostgreSQL would be extremely valuable.

Given the postgresql trigger is not supported in the custom metrics autoscaler offering today, it would be highly appreciated if it could be added as one of the supported triggers.
This is is already possible in upstream: 
https://github.com/kedacore/keda-docs/blob/main/content/docs/2.17/scalers/postgresql.md
A similar trigger was implemented here for the cron set up: https://issues.redhat.com/browse/RFE-4173

3. Why does the customer need this? (List the business requirements here)

Adding support for PostgreSQL triggers as a source of custom metrics in KEDA would enable development and operations teams to dynamically scale applications and pods in direct response to data-driven events stored in PostgreSQL.
Many businesses rely on PostgreSQL for real-time data storage in their mission-critical applications. The ability to dynamically scale these applications based on specific PostgreSQL triggers would significantly enhance performance and reduce response times during traffic spikes.

4. List any affected packages or components.
Custom Metrics Autoscaler (KEDA)