Provide clearer messaging from Get-SupervisorLog when supervisor is not running in a local windows studio

[mwrock]

Under some circumstances when the supervisor is not running in a local windows studio, the log window appears and then quickly disappears, which is very confusing. This either means that the supervisor failed to start or you are on a slow network and the supervisor may be in the midst of downloading and has not started yet. One reason that a local studio supervisor will fail to start is if you already have a supervisor running on the machine. In that case the hab studio enter output should say something to the effect that a supervisor is already running. I think we could improve this experience by:

1. Having Get-SupervisorLog report that there is a supervisor running elsewhere on the machine and no supervisor is running in this studio.
2. If it is in the process of starting a supervisor, either report that a supervisor is still starting or block until the supervisor has started.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. We value your input and contribution. Please leave a comment if this issue still affects you.