[grafana] SpiceDB dashboard: add graphs for cache hit/miss rate and ratio

[geropl]

Description

Check https://grafana.gitpod.io/d/tw0BBk-Vz/gitpod-components-spicedb?orgId=1&from=now-1h&to=now:

Summary generated by Copilot

🤖 Generated by Copilot at aff9707

This pull request enhances the observability of Spicedb, a service that handles authorization and data storage for Gitpod. It adds two new panels to the operations/observability/mixins/meta/dashboards/components/spicedb.json dashboard to show the cache hit and miss rates and the cache hit/miss ratio. These metrics help to monitor the performance and efficiency of the Spicedb cache.

Related Issue(s)

Part of EXP-738

How to test

Documentation

Preview status

gitpod:summary

Build Options

Build

• /werft with-werft
  Run the build with werft instead of GHA
• leeway-no-cache
• /werft no-test
  Run Leeway with --dont-test

Publish

• /werft publish-to-npm
• /werft publish-to-jb-marketplace

Installer

• analytics=segment
• with-dedicated-emulation
• workspace-feature-flags
  Add desired feature flags to the end of the line above, space separated

Preview Environment / Integration Tests

• /werft with-local-preview
  If enabled this will build install/preview
• /werft with-preview
• /werft with-large-vm
• /werft with-gce-vm
  If enabled this will create the environment on GCE infra
• with-integration-tests=all
  Valid options are all, workspace, webapp, ide, jetbrains, vscode, ssh. If enabled, with-preview and with-large-vm will be enabled.
• with-monitoring

/hold

[svenefftinge]

Let's see if that is the right metric. I find it strange that we already see cache hits.

[geropl]

/unhold