Add an optional ingress spec to Stream CRD

[thedodd]

• The Stream CR should allow for an ingress class to be specified.
• When the ingress object is present, Hadron will create and manage ingress objects for proxying traffic back to individual partition services based on hostname.
• Ingress object should have a domain field, which will be used to generate the hostname matchers for ingress entries. They will be formatted as {serviceName}.{domain}.
• Partition connection info should include the internal connection strings as {serviceName}.{namespace} and external connection strings if the stream is configured with ingress controls.
• Document how external connections should be established with k8s ingress, services, LBs, and how all of this works with the metadata system.
• update CLI docs.

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Maybe support a NodePort pattern as well. This would allow for easier interop with development clusters, and clusters where a simple nodeport setup is desired.

• operator would have to randomly assign nodeports for the services.
• a DNS name would need to be assigned as well which would resolve to at least one of the nodes of the cluster. Once it hits at least one node port, then k8s networking will get it to the correct location.
• this would be exclusive with ingress type for external access.