Upgrade to PostgreSQL 15.5

Successfully upgraded the Docker container on the Database Host by means of automated Watchtower container and on K3s Kubernetes Cluster by Flux V2 GitOps.

PostgreSQL 14.7
PostgreSQL 14.8
PostgreSQL 14.9
PostgreSQL 14.10
PostgreSQL 15.0
PostgreSQL 15.1
PostgreSQL 15.2
PostgreSQL 15.3
PostgreSQL 15.4
PostgreSQL 15.5

Including migrating datastore from version 14 to 15.