Configure Metrics Exporter Verbosity via Deployment Variables

[realyota]

Summary
Expose a configurable option (e.g., environment variable or Helm chart value) to adjust the metrics-exporter’s glog verbosity (-v flag) when deploying the ClickHouse Operator, reducing verbose logs without needing to manually override container args.

Problem Statement
The metrics-exporter defaults to -v=1, which can flood pod logs with detailed manifests and debug information. Currently, the only way to quiet these logs is to manually override the container’s command/args, which is error-prone and inconsistent across deployments.

Proposed Solution
Introduce a deployment-level variable—such as METRICS_EXPORTER_VLEVEL or a Helm chart value like metricsExporter.logVerbosity—that maps directly to the exporter’s -v flag. The operator or Helm chart would consume this variable and configure the container accordingly.

Alternatives / Workarounds
Currently, users can override the metrics-exporter container’s args to set -v=0, but this requires explicit changes in manifest files or Helm templates and is less discoverable.

Additional Context
This feature request stems from the need to reduce log noise in environments where verbose logs are unwieldy, yet operator logs must remain unchanged. Having a single configuration variable would streamline deployments and maintainability.