Add delete function to Preloader

[smuu]

call EmptyImages()

[salehshoji]

is this okay?

func NewPreloader() (*Preloader, error) {
	k8sName, err := generateK8sName("knuu-preloader")
	if err != nil {
		return nil, fmt.Errorf("error generating k8s name for preloader: %w", err)
	}
	preloader := &Preloader{
		k8sName: k8sName,
		images:  []string{},
	}
	err = preloader.EmptyImages()
	if err != nil {
		return nil, err
	}
	return preloader, nil
}

[smuu]

Thanks for the question @salehshoji :rocket:

I meant adding func (p *Preloader) Delete() error, which in the implementation can call EmptyImages().