[ModuleCatalog] Implement Logic for ModuleReleaseMeta CRD in Kyma Reconcile Loop

[jeremyharisch]

Description:

We need to implement the logic to utilize the newly created ModuleReleaseMeta CRD in the Kyma reconcile loop. Currently, we fetch and filter ModuleTemplates based on the channel specified in ModuleTemplate.spec. This logic needs to be updated to fetch the appropriate ModuleTemplate by using the information from the ModuleReleaseMeta CRD.

Detailed decision ticket: #1815

New Logic:

• In the Kyma reconcile loop:
  • Instead of fetching all ModuleTemplates and filtering by the channel specified in ModuleTemplate.spec, first fetch the ModuleReleaseMeta CR.
  • Use the channel specified in the Kyma.spec for the module.
  • Then, check the corresponding version from the ModuleReleaseMeta.spec.
  • Fetch the matching ModuleTemplate based on this version.
• Introduce a naming pattern for ModuleReleaseMeta to simplify the fetching process, it needs to be well-documented (just the module name).
  • Use the naming pattern for ModuleTemplate CRs as well (modulename-versionnumber)

Acceptance Criteria:

• Adapt the current implementation to follow the new logic of using ModuleReleaseMeta for fetching ModuleTemplates.
• Adapt all relevant tests to reflect this new functionality.
• Adapt existing documentation and add new feature documentation explaining the usage of ModuleReleaseMeta, including any naming patterns introduced.

[c-pius]

ModuleReleaseMeta CRs should be cached using a TTL cache

Can we really cache it? When it changes, we enqueue a reconcile event for the related kymas which should then fetch the up to date version, and not a maybe outdated one from the cache

Consider introducing a naming pattern for ModuleReleaseMeta to simplify the fetching process. If this is decided upon, the naming pattern needs to be well-documented.

I think the naming pattern must already be defines as part of #1848. But I think it can be as simple as the module name?

[janmedrek]

Depends on: #1848