Add patches to instead of statusTemplate in Stage

[wzshiming]

What type of PR is this?

/kind feature

What this PR does / why we need it:

Which issue(s) this PR fixes:

xref #922

Special notes for your reviewer:

kwok/pkg/apis/internalversion/conversion.go

Lines 394 to 447 in 60d7b64

	// Convert_v1alpha1_StageNext_To_internalversion_StageNext converts a v1alpha1.StageNext to an internal version.
	func Convert_v1alpha1_StageNext_To_internalversion_StageNext(in *v1alpha1.StageNext, out *StageNext, s conversion.Scope) error {
	err := autoConvert_v1alpha1_StageNext_To_internalversion_StageNext(in, out, s)
	if err != nil {
	return err
	}
	if in.StatusTemplate != "" && len(out.Patches) == 0 {
	template := in.StatusTemplate
	subresource := "status"
	if in.StatusSubresource != nil {
	subresource = *in.StatusSubresource
	}
	var impersonation *ImpersonationConfig
	if in.StatusPatchAs != nil {
	impersonation = &ImpersonationConfig{
	Username: in.StatusPatchAs.Username,
	}
	}
	patch := StagePatch{
	Subresource: subresource,
	Root: "status",
	Template: template,
	Impersonation: impersonation,
	}
	out.Patches = []StagePatch{patch}
	}
	return nil
	}
	// Convert_internalversion_StageNext_To_v1alpha1_StageNext is an autogenerated conversion function.
	func Convert_internalversion_StageNext_To_v1alpha1_StageNext(in *StageNext, out *v1alpha1.StageNext, s conversion.Scope) error {
	err := autoConvert_internalversion_StageNext_To_v1alpha1_StageNext(in, out, s)
	if err != nil {
	return err
	}
	if len(in.Patches) != 0 {
	patch := in.Patches[0]
	if patch.Root == "status" {
	out.StatusSubresource = &patch.Subresource
	out.StatusTemplate = patch.Template
	if patch.Impersonation != nil {
	out.StatusPatchAs = &v1alpha1.ImpersonationConfig{
	Username: patch.Impersonation.Username,
	}
	}
	}
	}
	return nil
	}

Old Structure:

spec:
  next:
    statusTemplate: <string>     # The status template.
    statusSubresource: <string>  # The status subresource. default: 'status'
    statusPatchAs:
      username: <string>         # The username to impersonate.

New Structure:

spec:
  next:
    patches:
    - subresource: <string>  # The subresource to patch. This could be '', 'status', 'spec', 'scale' etc. the '' is used to patch the entire resource. default: ''
      root: <string>         # The root of the template calculation. This could be '', 'status', 'spec', etc. the '' is used to patch the entire resource. default: ''
      template: <string>     # The template to apply. This is a string representation of the desired state.
      impersonation:         # The as section is used to impersonate a user or group.
        username: <string>   # User could be a regular user or a service account in a namespace.

Examples:

Update a replicas through the 'scale' subresource

spec:
  next:
    patches:
    - subresource: scale
      root: spec
      template: |
        replicas: 2

Update the 'status' but not is a subresource

spec:
  next:
    patches:
    - subresource: ''
      root: status
      template: |
        phase: Running

Does this PR introduce a user-facing change?

Add patches to instead of statusTemplate in Stage

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[k8s-ci-robot]

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This pull-request has been approved by: wzshiming

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