Add examples to all tk commands

cmd/tk/bootstrap_github.go

cmd/tk/bootstrap_gitlab.go

cmd/tk/create_kustomization.go

cmd/tk/create_source_git.go

cmd/tk/delete_kustomization.go

cmd/tk/delete_source_git.go

cmd/tk/export_kustomization.go

cmd/tk/export_source_git.go

cmd/tk/get_kustomization.go

cmd/tk/get_source_git.go

cmd/tk/reconcile_source_helm.go

cmd/tk/resume_helmrelease.go

cmd/tk/resume_kustomization.go

cmd/tk/suspend_helmrelease.go

cmd/tk/suspend_kustomization.go

cmd/tk/uninstall.go