document status dashboard needs bokeh better?

I embarrassingly struggled with this for quite some time and only really solved it after throwing PDBs in random places. I kept seeing that the dashboard link was `None` despite seemingly doing everything right.

All I needed to do was install `bokeh` 😂

I actually do see its documented here https://distributed.dask.org/en/latest/web.html#connecting-to-web-interface but being new to dask I didn't really know how all these libraries are connected.

P.S. tornado 6 works fine now so that can be removed from the sample EMR script