config: Exclude DB metrics by default
The extremely costly query executed by the read-only repository
Prometheus metric regularly causes customer outages after upgrades
to v14.3+. The addition of
PrometheusExcludeDatabaseFromDefaultMetrics
allows admins to avoid
this problem, but is not enabled by default.
This MR enables PrometheusExcludeDatabaseFromDefaultMetrics
by
default to help prevent future outages.