Add `#MatchLabelsComponent` generator to Timoni's CUE schemas

[Nalum]

This PR adds a generator for Kubernetes object selectors that will inject the app.kubernetes.io/component label to the selector. The example below makes use of the #MetaComponent introduce in #270.

Example:

#Deployment: appsv1.#Deployment & {
        _config:    #Config
        _component: "test"

        apiVersion: "apps/v1"
        kind:       "Deployment"

        _metadata: timoniv1.#MetaComponent & {
                #Meta:      _config.metadata
                #Component: _component
        }

        metadata: _metadata

        spec: appsv1.#DeploymentSpec & {
                replicas: _config.replicaCount
                selector: timoniv1.#MatchLabelsComponent & {
                        #SelectorLabels: _config.selector.labels
                        #Component:      _component
                }

                template: {
                        metadata: labels: _metadata.labels

                        if _metadata.annotations != _|_ {
                                metadata: annotations: _metadata.annotations
                        }
                }
        }
}

[stefanprodan]

@Nalum please see https://github.com/stefanprodan/timoni/pull/270 that exposes the selector directly from Metadata without the need for an extra helper. Also in your example above, you set the template labels to the metadata.labels, but these should be set to the selector value.

[Nalum]

Happy to close this in favor of the changes you've setup in #270.