Live restore has a phase where to work around some of the intricacies created by log replay it copies over the log files prior to live restore beginning. If we implement atomic file copy in live restore, by copying to a temporary file and then moving that file to the actual name we can avoid needing this log copy phase.

Additionally by implementing atomic file copy we can support copy-on-open of regular files such as the turtle file and the basecfg file as they do not have an alloc_size which the bitmap implementation depends on.