Enable pg exporter in Stackgres

[steven-sheehy]

Problem

To help with https://github.com/hashgraph/hedera-mirror-node/issues/9355, we need more metrics to gain insight into the internals of PostgreSQL.

Solution

• Enable pg exporter sidecar
• Enable any metrics options that we need
• Disable any high cardinality metrics we don't need or can't afford
• Add custom metrics to exporter for pg_stat_io to specifically capture memory
• Enable pg_buffercache extension in v2 and add custom metrics for it
• Import and tweak the Grafana dashboards
• Import relevant alerts

Alternatives

No response