[feature request] Do we miss delete all resource for yurt-app-manager

[adamzhoul]

see DeployYurtAppManager when yurtctl convert

openyurt/pkg/yurtctl/util/kubernetes/apply_addons.go

Line 60 in c50a8d0

func DeployYurtAppManager(

it does:

1. create CRD:                                  nodepool uniteddeployment
2. create Role:                                 yurt-app-leader-election-role
3. create ClusterRole:                          yurt-app-manager-role
4. create RoleBinding:                          yurt-app-leader-election-rolebinding
5. create ClusterRoleBinding:                   yurt-app-manager-rolebinding
6. create secret:                               yurt-app-webhook-certs
7. create service:                              yurt-app-webhook-service
8. create deployment:                           yurt-app-manager
9. create MutatingWebhookConfiguration:         yurt-app-mutating-webhook-configuration
10. create ValidatingWebhookConfiguration:      yurt-app-validating-webhook-configuration

but can't find any delete in yurtctl revert

besides：

openyurt/pkg/yurtctl/cmd/revert/revert.go

Line 178 in c50a8d0

// 3.1 remove the serviceaccount for yurt-controller-manager

why not put remove `yurt-controller-manager` resource in a function in apply_addons.go 
so deploy /delete can put together.

others
/kind feature

[rambohe-ch]

@adamzhoul Thank you for raising issue.
In fact, @yanyhui has made a pull request for this feature: #393, and some errors and comments have been not fixed.