Expose progress hook for elapsed time as a proportion of expected total time in sample

[fivegrant]

Terarium now requires progress bars for simulate, however, I imagine that this will be requested individually for each operation over time. As long as there is a progress_hook, we can bubble it up to the interface

[SamWitty]

Hi @fivegrant , could you please break this out into one issue for each of the specific operations/intermediate results you'd like us to support. For example, Expose progress hook for elapsed time as a proportion of expected total time in simulate. This will help keep us focused on what's really important for TA4.

[fivegrant]

@SamWitty I just changed this issue to only include simualte since that's actually what's being requested.