document advised log settings and retention for PostgreSQL backend

In order to diagnose potential database issues using Postgres with repository manager, Sonatype should document our recommended settings for PostgreSQL log retention and settings. Should a problem occur with repository manager that involves the database, the PostgreSQL logs should be retained long enough and have enough detail to diagnose any reasonably anticipated problems.

https://www.postgresql.org/docs/12/logfile-maintenance.html
https://www.postgresql.org/docs/12/runtime-config-logging.html#RUNTIME-CONFIG-LOGGING-WHERE

Expected

help.s.c section that advises our recommended log settings for PostgreSQL standalone and Amazon Aurora PostgreSQL flavour.