Include application side detail in prometheus metrics

Currently, prometheus metrics only contain the IP address and the job name. It would be nice to include additional details such as turbinia instance id, whether it's a server/worker, etc. We can then use these fields for better alerting and monitoring

Start by locating Turbinia's Prometheus metrics entry point and reviewing how the IP address and job name are currently exposed. Clarify the desired labels, including instance ID and server/worker role, then define acceptance checks for their presence and usefulness for alerting and monitoring.

Written by the indexing model from the issue text.