Advertise support

In a meeting this afternoon around corporate engagement, @datametrician requested that we advertise how companies can engage and get help, other than going to public methods. When we pointed out the current [paid support](https://docs.dask.org/en/latest/support.html#paid-support) section this seemed to be ok, but wasn't sufficiently prominent. The request was to put this more visibly on the main doc page, and also possibly on dask.org.

Do we want to do this?

(disclaimer, I work for a company that would probably benefit from this action)