Allow per job client defined configuration of job metrics.

This shouldn't have to synchronized between Galaxy and Pulsar - Galaxy should be able to define this with the job request.

The issue names no files or tests. Start by tracing the Galaxy job request into Pulsar and identify where job metrics configuration is currently synchronized; done means a job request can carry client-defined metrics settings without requiring Galaxy and Pulsar to share that configuration.

Written by the indexing model from the issue text.