SKIP UPGRADE: PLG stack

Package Owner Merge Request

Package Changes

• Added promtail package:
  • If Loki is also deployed via BB, promtail will automatically be configured to send logs to the endpoint (see chart/templates/logging/promtail/values.yaml)
• Added loki package.
• Modified monitoring package:
  • If loki is deployed via BB, automatically add it as a data source in Grafana (see chart/templates/monitoring/values.yaml)

This PR depends on the initial-work branches of the Promtail and Loki sandbox packages.

Additional Details

Known issues / needs to be reviewed

• .Values.logging.enabled as mentioned above
• Needs to be tested with Istio enabled
• Loki ServiceMonitor should be enabled by default if logging.loki.enabled = true so Prometheus can gather metrics about it

Closes #937 (closed)