[ModuleCatalog] Add .spec.manager info to ModuleTemplate

[c-pius]

Description

In #1681 it has been decided to add explicit information identifying a module's manager to the ModuleTemplate. We need to update the ModuleTemplate to include this information.

The information shall look as follows:

spec:
  manager:
    group: <group>
    version: <version>
    kind: <kind>
    namespace: <namespace>
    name: <name>

.spec.manager is OPTIONAL (for compatibility reasons), but the individual entries are REQUIRED, except Namespace which can be OPTIONAL due to CRDs not being namespaced. It should be checked whether existing K8s types and validations can be re-used.

Reasons

Enables CLI and dashboard to determine whether a module is installed or not (manual installation case)

Acceptance Criteria

• re-used K8s types if possible
• .spec.manager added to ModuleTemplate
• Added an entry to Modularization API Upgrade #776 that .spec.manager must be added as required in a future major API version

Feature Testing

No response

Testing approach

No response

Attachments

No response

[janmedrek]

Let's reconsider other options such as introducing a new resource just for CLI/UI monitoring purpose.

[c-pius]

Discussed this quickly in the arch meeting today. PB (not present, only left a comment), is okay with the proposal that an arbitrary resource may be provided. If the resource is present, it is assumed that the module is installed in the cluster. We can make the namespace optional to support cluster scoped resources.

Still, the expected resource to be provided is the module manager (deployment). Should we nevertheless rename the field or keep manager?