[PVC][chore] remove contentDescriptorToLayer in favor of contentDescriptorToLayerPVC

[sagor999]

After this PR gets merged, we should harmonize contentDescriptorToLayerPVC and contentDescriptorToLayer by switching to using /.workspace' folder to place content.json file, instead of placing it into /workspace` folder, and thus removing a separate code path for PVC implementation.
For more info: #9242 (comment)

[sagor999]

This doesn't quite work for old way of doing things, since ws-daemon attempts to place content.json into /workspace folder:

gitpod/components/ws-daemon/pkg/content/initializer.go

Line 126 in c1cd9bb

func RunInitializer(ctx context.Context, destination string, initializer *csapi.WorkspaceInitializer, remoteContent map[string]storage.DownloadInfo, opts RunInitializerOpts) (err error) {

It is not clear how easy it would be to change that function, and I don't think it will be worth the effort (and potential unaccounted edge cases)
So I think it is best to just remove old contentDescriptorToLayer once we 100% switch to PVC.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[sagor999]

Changed title of the issue.
Once PVC is fully working, remove old code path instead of trying to merge those two together in the meantime.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.