Add `.get_client()` method to Cluster class

I’m sitting with @costrouc and he’s typing cluster.get_client() based on his experience with Dask Gateway. Should we upstream this to dask.distributed.deploy.Cluster?

cc @jacobtomlinson @jcrist

[jsignell]

I agree that the mulitple imports isn’t very elegant and would totally support an implementation like I outlined in https://github.com/dask/distributed/issues/6732#issuecomment-1187674320

[mrocklin]

Mostly the concern that I feel is when writing basic materials I have to ask users to import different things from different libraries.

from dask_jobqueue import SLURMCluster
cluster = SLURMCluster()

from dask.distributed import Client
client = Client(cluster)

I remember reading Spark materials and getting confused about the Conf and Session and SQLSession objects that I had to create. The ceremony to get a basic example running felt odd.

Adding Cluster.get_client would let us rework our common basic example to the following:

from dask_jobqueue import SLURMCluster
client = SLURMCluster().get_client()

Not a big deal. My guess is that it’s less friction for early users. Not a big deal though.