Only postgres database stats are collected by postgres-exporter

Some of the current dashboard panels show only information about the postgres database and non of the other.

Also, the current Postgres-exporter configuration has the queries.yml file inside the image and this makes it more difficult to update the configuration.

Configuration should be like:

1. A configmap with the queries.yaml content to be mounted to the postgres-exporter image.
2. Add this environment variables to the postgres-exporte sidecar:

• DATA_SOURCE_NAME= connection string to postgres database
• PG_EXPORTER_EXTEND_QUERY_PATH: "/var/opt/postgres-exporter/queries.yaml" (This could be any other path)
• PG_EXPORTER_AUTO_DISCOVER_DATABASES: "true"
• PG_EXPORTER_EXCLUDE_DATABASES: "template0,template1"