Run dashboard on non-standard port and set dashboard link

[jacobtomlinson]

It looks like when running Ray clusters on Databricks there is a way to access the dashboard.

https://docs.databricks.com/en/machine-learning/ray-integration.html

It seems that on Databricks you can proxy arbitrary ports via /driver-proxy/o/{orgId}/{clusterId}/{port}/. But when we try it with the Dask dashboard we see a 403 error.

This PR starts the dashboard on a few additional ports, including 8265 which is used by Ray's dashboard to see if 8787 is being explicitly blocked. It looks like Databricks just blocks 8787 for some reason, so this PR starts the Dask dashboard on 8087 too in case users want to run both Dask and Ray on the same cluster.

Also, set the dashboard_link to the correct URL.

Closes #2

[jacobtomlinson]

I've been trying this out and the dashboard page loads, but not correctly. It looks like it's because of some absolute URLs in the Bokeh resources. This only seems to happen with the latest bokeh==3.3.0 and downgrading to 3.2.2 works around it.

[jacobtomlinson]

It works!