[ContBk] Build & restore a manifest at a point in time from collection events

In order to correctly restore to a point in time we need to know what collections existed at that point. To do that we will take the collection from the tradition restore and use the separate collection events file (created in MB-62258) to replay collection events on top of it for each vBucket until we reach a collection event past the restore timestamp.

This will leave us with a manifest per vBucket at the restore timestamp, and we will take the one with the highest manfiest UID. This is the manifest we will then restore to the cluster.