Controller should allow an empty CPU resource limit

[sravi999]

/kind bug

What steps did you take and what happened:
[A clear and concise description of what the bug is.]
The controller should allow an empty CPU resources limit when the CPU limit is empty.

What did you expect to happen:
If the CPU limit is empty don't set a default value for the CPU.

Anything else you would like to add:
[Miscellaneous information that will assist in solving the issue.]

Environment:
AWS EKS

• Kubeflow version (kfctl version): V1.1
• Minikube version (minikube version):
• Kubernetes version: (use kubectl version): V1.17
• OS (e.g. from /etc/os-release):

[sravi999]

cc: @andreyvelich

[andreyvelich]

Thank you for creating this @sravi999.
For all resources we can follow the Ephemeral Storage policy to remove them: https://github.com/kubeflow/katib/blob/master/pkg/util/v1beta1/katibconfig/config.go#L291.

/assign @andreyvelich