Client controllable "info" area in dashboard status page

The dashboard "status" page is useful for monitoring job execution.

However, in many workflows, it's common to have multiple job stages (query 1, query 2, query n). At a glance, one can't easily tell from the dashboard which stage is currently executing (and thus to get a sense of overall workflow progress). Typically I inspect a job log file or terminal output to get that sort of application specific info.

It would be nice for the dashboard to support (possibly via the `client` API?) displaying some user controllable text on the status page.

For example, in a 10 query job, I'd like to programmatically set something like:
```
Currently Executing: query 4/10
Started at 2022-7-14 12:00:00
```