feat: add /api/v1/rules endpoint

[yama6a]

Adding a prometheus-compatible API endpoint to rule-evaluator: /api/v1/rules

Unfortunately I couldn't fully make use of make presubmit and make e2e - something makes Colima explode. 🤷 Please let me know if there's anything missing or not as expected/required.

[yama6a]

Thanks for the quick review! 🙂

I attended to your comments and got parts of the CI check to run on my machine to validate it. The issues should (hopefully) be resolved now.

[yama6a]

@bwplotka seems like something in the pipeline is failing. Running the failing bin step locally, I get the same error. Anything I can do on my end to fix it?

[bwplotka]

Don't worry about the error, fixing in https://github.com/GoogleCloudPlatform/prometheus-engine/pull/1155

I checked and rule-evaluator step was done, so we can safely merge https://github.com/GoogleCloudPlatform/prometheus-engine/actions/runs/10990949209/job/30521085208?pr=1149#step:3:234

[pintohutch]

Fixed #291