Removal of task list from Porch API

[ciaranjohnston]

Porch APIs are documented here:
https://github.com/nephio-project/porch/blob/main/api/porch/v1alpha1/types.go

The PackageRevisionSpec struct includes parameter "Tasks":
https://github.com/nephio-project/porch/blob/9b4e2265ca04db7466d69ac0266de1cedfdc9d79/api/porch/v1alpha1/types.go#L100

which is an array of the operations performed on the packagerevision. These are essentially a replayable history of the packagerevision. They are only populated by Porch so a packagerevision which is not created by Porch may have an empty task list.

This tasks list seems to be something that either should not be exposed at all over the API (as an internal implementation detail of the package evolution structure) or something that needs to be clearly documented on how it should be populated, manipulated and evolved.

This issue is a result of a discussion around this user story proposal:
https://docs.google.com/document/d/1d4USe4nOcOQAb0ULCMGSPtC72f0dbV0SguPCPEGYaac/edit?tab=t.0

[ciaranjohnston]

Since certain aspects of the task list are used e.g. by PackageVariant a clear alternative needs to be in place (e.g. hidden from the API or well documented and understood, or replaced with a simpler / better parameter).