Show the worker tag name (and its description in a tooltip) in the job
details. When no worker tag is assigned, "All Workers" is shown in a more
dimmed colour.
This also renames the "Type" field to "Job Type". "Tag" and "Type" could
be confused, and now they're displayed as "Worker Tag" and "Job Type".
The UI in the add-on's submission interface is also updated for this, so
that that also shows "Worker Tag" (instead of just "Tag").