Automatically trim terminated worker rows in tasks and status tabs of the bokeh dashboard

When using adaptive clusters such as `KubeCluster` with `cluster.adapt(minimum=4, maximum=32)` for instance, each call to a parallel operation can potentially lead to the creation of very transient workers (which is good to share compute resources with other users of the same kubernetes cluster).

However, this quickly leads to many empty rows in the tasks tab making it unreadable after issuing several parallel calls with dasks (e.g. `.persist()` or `.compute()`).

Would it be possible to automatically trim or collapse the empty rows in the task view?

Adding the id or name of the workers as ticks on the y-axis would also be very helpful to make it easier to interpret this tab.