Switch to Using Istio for Auth(z)

[KPostOffice]

Name of Feature or Improvement

#298 (comment)

Use Istio/Service Mesh so that the end user doesn't need the elevated permissions we see with the current implementation.

Description of Problem the Feature Should Solve

Auth needs to gate access to both the dashboard api and the dashboard ui which are served on the same port.

Describe the Solution You Would Like to See

code is added to ODH operator most likely which automatically puts Service Mesh auth in front of Ray cluster dashboard