Added seed data to prometheus

[leandregagnonlewis]

Enable Prometheus Recording Rule Backfilling for Testing

This PR enhances the Docker Compose setup for development and testing by adding support for pre-seeding Prometheus with recording rule data. This change:

1. Modifies the Prometheus service in our docker-compose.yaml to use a custom entrypoint script
2. Adds a backfilling mechanism that generates 5 hours of historical data for a test recording rule
3. Re-enables a previously skipped Prometheus range query test that now has sufficient historical data to work with

Details

• Created a custom entrypoint script (testdata/prometheus-entrypoint.sh) that:

  • Starts Prometheus initially to make its API available
  • Uses promtool tsdb create-blocks-from rules to backfill 5 hours of data for a simple test recording rule
  • Restarts Prometheus to ensure the backfilled data is immediately available

• Added a simple recording rule definition in testdata/prometheus-seed.yml that creates a metric called test with a constant value of 1

• Updated our test to use the new test metric instead of up, removing the skip annotation since we now have predictable data to test against

This change will make our tests more reliable by ensuring consistent test data is available, regardless of how long the Prometheus instance has been running.

[csmarchbanks]

Love the solution, thanks!