feat(frontend): Support custom head scripts / analytics tags via Helm configuration

Problem

When deploying DataHub via Helm on Kubernetes, there is currently no straightforward way to inject analytics or observability scripts into the frontend without maintaining a custom frontend image.

Examples include:

• Umami Analytics
• Umami Heatmaps (recorder.js)
• Microsoft Clarity
• Google Tag Manager
• Internal telemetry solutions

Today the only apparent option is modifying the DataHub frontend source and publishing a custom datahub-frontend-react image.

Proposed Solution

Allow operators to inject custom scripts into the frontend through configuration.

Example:

datahub-frontend:
  customHeadScripts:
    - src: https://analytics.example.com/script.js
      defer: true
      attributes:
        data-website-id: abc123

    - src: https://analytics.example.com/recorder.js
      defer: true
      attributes:
        data-website-id: abc123
``