Add a document to outline the default settings for rayStartParams in Kuberay

[Yicheng-Lu-llll]

Why are these changes needed?

This PR:

• Add a document to outline the default settings for rayStartParams in Kuberay(see here for the ray start cli).
• The option dashboard-host will now be automatically injected with the value '0.0.0.0'.
• removes option num-cpus in all sample yaml file. The num-cpus value should be automatically determined based on the container.resource.cpu.limit. Refer to add resource command #170 for more information.

TODO:

• Remove option dashboard-host after releasing 0.6.0 and change the document accordingly.

Related issue number

Closes #976

Checks

I have run all the sample yaml files and fetched the ray start command to make sure all the options Kuberay may set by default for rayStartParams are included.

for file in $rootPath/ray-operator/config/samples/ray-cluster*.yaml
do
  echo "###########################"  >> $outputFile

  echo $file >> $outputFile

  kubectl apply -f $file
  sleep 5
  kubectl get  $(kubectl get pods -o=name | grep head) -o yaml | grep "ulimit -n 65536; ray start" >> $outputFile
  kubectl get  $(kubectl get pods -o=name | grep worker) -o yaml | grep "ulimit -n 65536; ray start" >> $outputFile
  kubectl delete -f $file
  sleep 90

  echo "###########################\n"  >> $outputFile
done
  echo "###########################\n"  >> $outputFile
done

[kevin85421]

@DmitriGekhtman would you mind reviewing the option --no-monitor?

[kevin85421]

LGTM.