DevDiagnostics: should have a status bar

[andreww-msft]

Suggested new feature or improvement

Increasingly, we're executing operations where the user could benefit from some feedback. Eg

1. Invoke some external tool. Perhaps it showed UI, perhaps it didn't. Perhaps it's not a UI tool. Perhaps our tool configuration of the path is stale? Perhaps it crashed? Or our command-line config is wrong? Either way, we should tell the user what's going on.
2. Exceptions within PI itself. Right now, we're logging them. Consider exposing this log output.
3. ...and make it a user setting: expose log output in the UI, and/or make log output file available.

...etc

Scenario

Consider options:

1. Simple one-line ephemeral status.
2. Status control with history.
3. both the above (togglable, and toggle persisted via user setting).

Additional details

No response