feat: Read component descriptor from oci registry

[Tomasz-Smelcerz-SAP]

Description

Note to reviewers: I was really trying to keep this PR as minimal as possible. There are many things to fix/improve/cleanup and many times I've seen that, but I decided not to, in order to introduce as few changes as possible.
Keep that in mind when suggesting improvements. Do we really want to make this PR even bigger? I would rather prefer to make a note in the sources and then create a follow-up PR to clean all the notes. Just remember that the work remaining in #2526 and our other efforts (like simplifying/getting rid of templatelookup.go) will probably make most of these review-fixes obsolete or unnecessary.
Up to you.

Changes proposed in this pull request:

• Component Descriptors (CD) are now read from the OCM repository (which usually is some OCI registry)
• To read a CD, one must provide an OCM Component Name and a version. In our current setup, the OCM Component Name is available only in a ModuleReleaseMeta for a given Module.
• It means that with this PR the ModuleReleaseMeta becomes mandatory
• To keep this PR minimal, I did not remove code/tests related to the previous "modes" of operation, where CD was fetched from a ModuleTemplate and ModuleReleaseMeta was, in some cases, optional. This code requires cleanup in a separate PR. Of course when the test is failing, I had to refactor it
• An interesting case: What to do if user configures a Module for which there is no ModuleReleaseMeta? Currently, when user configures a module on a Kyma, for which there's no ModuleTemplate, the Kyma is put in Warning state. To keep it consistent, I use the same error->status resolution strategy. To be discussed.
• Code coverage for some packages (templatelookup) decreased. This is because some test cases were disabled. This is (mostly) a legacy code that will disappear anyway. A new method of resolving ModuleTemplates along with ModuleReleaseMeta should be introduced, but this is not a part of this PR. I think it is OK to temporarily "lower the bar" - we're in the middle of a bigger refactoring here. Related issues that will introduce the necessary cleanpup/changes are listed are listed here
• There is an open discussion that focuses on the little detail: The OCI registry URL. Previously it was taken from the static ComponentDescriptor data embedded in the ModuleTemplate. Now we have at least two different values we can use: An explicitly configured one and the one from ComponentDescriptor, after it is successfully fetched (we still need OCI Registry URL for subsequent operations, like raw-manifest fetching). Which URL to choose? Please take a look at the discussion. I decided to rely on explicitly provided value as I had no feedback that I should chose a different strategy here.

Related issue(s)
#2601

[github-actions]

❌ Manifests created with 'make dry-run-control-plane' changed! Please make sure to check if changes are needed in related repositories like management-plane-charts, runtime-watcher, etc.

[Tomasz-Smelcerz-SAP]

We are blocked here by: <internal-repo>/kyma/test-infra/issues/781 - we need all the ModuleReleaseMeta to have OCM version related attributes. In particular spec.mandatory.version

[github-actions]

⚠️ Pipeline-related file changes detected! Please review if related updates (e.g. manifest generation or workflow adjustments) are required.

[github-actions]

❌ Manifests created with 'make dry-run-control-plane' changed! Please make sure to check if changes are needed in related repositories like management-plane-charts, runtime-watcher, etc.

[c-pius]

I admit that the sheer size of this PR reduces my confidence that everything is okay. It's just hard to really understand everything that is going on. But I think it should be good, we need to get forward at some point.

Let's be careful when this is rolled out. We should explicitly observe how it is working on DEV first. Maybe via a PR-deploy so that it isn't promoted to STAGE automatically.

[lindnerby]

Agree with the previous comment. Let's do an explicit rollout to DEV first via PR deploy. 👍

[c-pius]

And thanks a lot @Tomasz-Smelcerz-SAP for all the effort you put into this!