Replace multiple ResourceMeta implementations with a single type

[lobkovilya]

Description

We have 9 different implementations of meta spread across various packages and 1 ResourceMeta interface in the core package. This has downsides:

• introducing/changing fields in ResourceMeta requires changes in 9 files
• common shared functions that work with ResourceMeta can't be implemented as methods and have to accept ResourceMeta interface, see GetDisplayName, IsReferenced, ResourceOrigin
• we can't clone meta, instead we do hacks like this or this when we replace source meta with another ResourceMeta implementation

Single ResourceMeta type in core will be enough. ResourceMeta clients in various packages can create their own interfaces if needed.

type ResourceMeta struct {
	name             string
	version          string
	mesh             string
	creationTime     time.Time
	modificationTime time.Time
	labels           map[string]string

	nameExtensions map[string]string // kube specific
	annotations    map[string]string // kube specific
}

When it comes to KubernetesMetaAdapter, we don't have to store the entire v1.ObjectMeta object. We need to store only annotations and UID (UID can be encoded to meta.version like {.ResourceVersion}/{.UID}):

// kube meta -> core meta
func ResourceMeta(objectMeta *v1.ObjectMeta, mesh string) *core_model.ResourceMeta {
	var name string
	if objectMeta.Namespace == "" {
		name = objectMeta.Name
	} else {
		name = util_k8s.K8sNamespacedNameToCoreName(objectMeta.Name, objectMeta.Namespace)
	}
	labels := maps.Clone(objectMeta.GetLabels())
	if labels == nil {
		labels = map[string]string{}
	}
	if displayName, ok := objectMeta.GetAnnotations()[v1alpha1.DisplayName]; ok {
		labels[v1alpha1.DisplayName] = displayName
	} else {
		labels[v1alpha1.DisplayName] = objectMeta.GetName()
	}
	return (&core_model.ResourceMetaBuilder{}).
		WithName(name).
		WithMesh(mesh).
		WithVersion(strings.Join([]string{objectMeta.GetResourceVersion(), string(objectMeta.UID)}, "/")).
		WithCreationTime(objectMeta.GetCreationTimestamp().Time).
		WithModificationTime(objectMeta.GetCreationTimestamp().Time).
		WithLabels(labels).
		WithAnnotations(objectMeta.GetAnnotations()).
		WithNameExtensions(ResourceNameExtensions(objectMeta.Namespace, objectMeta.Name)).
		Build()
}

// core meta -> kube meta
func ObjectMetaAndMesh(meta *core_model.ResourceMeta) (*v1.ObjectMeta, string) {
	labels, annotations := SplitLabelsAndAnnotations(meta.GetLabels(), meta.GetAnnotations())
	versionAndUID := strings.Split(meta.GetVersion(), "/")
	return &v1.ObjectMeta{
		Name:              meta.GetNameExtensions()[core_model.K8sNameComponent],
		Namespace:         meta.GetNameExtensions()[core_model.K8sNamespaceComponent],
		Labels:            maps.Clone(labels),
		Annotations:       maps.Clone(annotations),
		CreationTimestamp: v1.Time{Time: meta.GetCreationTime()},
		ResourceVersion:   versionAndUID[0],
		UID:               types.UID(versionAndUID[1]),
	}, meta.GetMesh()
}