[feature request] idempotent when execute yurtctl convert or yurtctl revert

[adamzhoul]

What would you like to be added:

whenever we execute yurtctl convert or yurtctl revert
no matter how many times we execute (same command)

it shall succeed, has no side effect.

Why is this needed:

reduce user mind pressure when try and execute
try yurtctl with different params when last is wrong and failed, without execute yurtctl revert and delete failed k8s job manually.

others
/kind feature

for example:

 yurtctl-disable-node-controller  using sed, multiple execute leads to multiple `-nodelifecycle`

nsenter -t 1 -m -u -n -i -- sed -i 's/--controllers=/--controllers=-nodelifecycle,/g' {{.pod_manifest_path}}/kube-controller-manager.yaml

manually delete k8s job when last is failed. 

[rambohe-ch]

@adamzhoul Thank you for raising issue.

when user want to convert a native k8s cluster to OpenYurt, yurtctl convert/revert is not a cloud native solution. so another solution(add an yurtcluster operator) has been raised by @gnunu and @SataQiu . you can reference the following issues and docs:

• [feature request] Should an Operator be good to turn vanilla k8s cluster to OpenYurt one? #328
• [Feature] Introduces one basic implementation of an OpenYurt Operator #427
• https://github.com/openyurtio/openyurt/blob/master/docs/proposals/20210722-yurtcluster-operator.md

and we are looking forward to YurtCluster operator ready.

[adamzhoul]

operator is certainly a better solution.