Add PostgreSQL and Prometheus options to cncli-leaderlog.sh
Save the complete leaderlog (with or without scheduled slot time) to a PostgreSQL table. Included a function to test the connection to Postgres using 'cncli-leaderlog.sh --test --postgres'. Write the total number of assigned slots for an epoch to file in a format readable by Prometheus, so it can be used in a Grafana dashboard. Added command line flags to force calculation and processing of the previous plus current and next epoch.