Support use of ingress for accessing ray dashboard when ray cluster is created.

[MichaelClifford]

The current implementation of "cluster.up()" generates a route resource to expose the ray dashboard to the internet. However, routes are specific to OpenShift and not available in vanilla kubernetes. We should add support for using ingress resources as well which can be used with kubernetes.

This should also address the issue here:
#143 (comment)

[Maxusmusti]

Note that our cluster.cluster_dashboard_uri() should then also utilize the ingress API as opposed to the routes API (similar to what is being done currently in cluster.local_client_url()