Add documentation for KubeOps operation "delete"

[muffl0n]

Change Overview

KubeOps was introduced in #1102 but documentation for operation "delete" is missing from "Kanister Functions".

Pull request type

Please check the type of change your PR introduces:

• 🚧 Work in Progress
• 🌈 Refactoring (no functional changes, no api changes)
• 🐹 Trivial/Minor
• 🐛 Bugfix
• 🌻 Feature
• 🗺️ Documentation
• 🤖 Test

Issues

• Support delete operation in kubeops function #1102

Test Plan

• 💪 Manual
• ⚡ Unit test
• 💚 E2E

[muffl0n]

Resulting docs:

[ihcsim]

This LGTM 👍. While you are here 😉, can you also help us to add the Outputs subsection to describe the function outputs? Looking at the code, these should be the relevant fields 👉

kanister/pkg/apis/cr/v1alpha1/types.go

Lines 58 to 75 in c71b5aa

	// ObjectReference refers to a kubernetes object.
	type ObjectReference struct {
	// API version of the referent.
	APIVersion string `json:"apiVersion"`
	// API Group of the referent.
	Group string `json:"group"`
	// Resource name of the referent.
	Resource string `json:"resource"`
	// Kind of the referent.
	// More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#types-kinds
	Kind string `json:"kind"`
	// Name of the referent.
	// More info: http://kubernetes.io/docs/user-guide/identifiers#names
	Name string `json:"name"`
	// Namespace of the referent.
	// More info: http://kubernetes.io/docs/user-guide/namespaces
	Namespace string `json:"namespace,omitempty"`
	}

. Thanks!

[muffl0n]

As I'm on maternity leave at the moment, I don't have the time. But this PR can surely be merged without the outputs. Documentation for this function might not be perfect, but a step in the right direction.