Add process status to tasks

[noahmehl]

Overview

As a user, it would be convenient to see the process_status value for a compaction job. This is because smoosh may start a compaction job and have some progress before suspending it because it's outside the window for processing.

Testing recommendations

GitHub issue number

This is to address this issue: https://github.com/apache/couchdb/issues/3816

Related Pull Requests

N/A

Checklist

• [x] Code is written and works correctly;
• [ ] Changes are covered by tests;
• [ ] Documentation reflects the changes;
• [ ] Update rebar.config.script with the correct tag once a new Fauxton release is made