Build metrics only partially updated

[anothertobi]

The metrics on builds currently exposed are only partially updated. It would be good to have more metrics updated to extend our monitoring.

Based on the code it looks like only lagoon_builds_running_current and lagoon_builds_started_total are filled with data while the other metrics are just initialized with 0.

[shreddedbacon]

These are not really reliable metrics to use for monitoring and alerting, more visibility. If monitoring and alerting are a requirement, then additional work would need be done to ensure the reliability of these metrics

[anothertobi]

Right now these metrics would be used by platform for visibility only on a Grafana dashboard and not to create alerts. Especially interesting to see would be lagoon_builds_pending_current.