feat: publish pre-compiled dashboards and recording rules

[manab-pr]

Fixes #3624

Added ready-to-use, pre-compiled Grafana dashboards and Prometheus recording rules so users can import them directly without needing to install jsonnet/jb dependencies or compile the mixin themselves.

This addresses the issue where users with build constraints cannot compile the dashboards, alert rules, and recording rules from source.

Changes:

• Added operations/pyroscope/mixin-compiled/ with compiled artifacts
  • 2 Grafana dashboards (pyroscope-reads.json, pyroscope-writes.json)
  • Prometheus recording rules (30 pre-computed metric rules)
  • Alert rules placeholder for custom alerts
  • Metadata file with build information
• Created scripts/compile-mixin.sh for automated compilation
• Added make compile-mixin and make check/mixin-compiled targets
• Added GitHub Actions workflow to auto-update compiled files on source changes
• Updated documentation in README.md and operations/pyroscope/jsonnet/README.md

[CLAassistant]

All committers have signed the CLA.

[simonswine]

@manab-pr thank you so much for your work on this, I am also working right now in this area, I have went a slightly different route: #4525.

Basically those dashboards are pretty outdated and mismatching what we are using internally. The idea is that we move our dashboards upstream (with slightly templating), so they work for bare OSS too.

I think having the dashboards/rules generated and published as part of generated code or included in the weekly release is super helpful, I will see if I can integrate this as well.

[manab-pr]

@simonswine Thank you for the feedback! I appreciate you letting me know about #4525.
I'm happy to see that the dashboards are being updated with your internal versions - that sounds like it will provide much better value for users. My main goal was to address the compilation issue for users who can't install
jsonnet/jb dependencies.
Since you mentioned wanting to integrate the publishing/generation workflow, would it be helpful if I:
Close this PR in favor of #4525, or
Adapt my compilation script and GitHub Actions workflow to work with your updated dashboards?

I'm flexible either way and happy to contribute whichever approach works best for the project. Let me know how I can help!

[simonswine]

I think probably the best approach would be to close this PR for now (sorry for all the work you put in) and then I would like your input on #4525 (once I mark it ready to review). So I can understand if these dashboards work for you/your environment and what we can approve to simplify adoption.

I likely will update some of the makefile targets to ensure we generate a folder with dashboards and rules from the templating defined in the helm chart.

[manab-pr]

No worries at all! I'm happy to close this PR , I'd be glad to review and test #4525 once it's ready . Looking forward to seeing your approach with the helm chart templating ,that sounds like a cleaner solution. Feel free to tag me when #4525 is ready for review and I'll test it against my setup.
Thanks for being so collaborative on this!