[Feature] Handle `sed` of kubeconfig in hln and pass ready-to-use one to stack

[hongchaodeng]

sed might behave differently depending on the platform (mac, linux, etc.)

[vgjm]

I will add the ability of sed -e 's?server: https://.*?server: https://kubernetes.default.svc?' into hln.
Should I add a hidden internal hln util sed command or should I do this with a flag of hln check or other commands?

[hongchaodeng]

After discussion, we will add a CUE action to handle this which is more elegant.