Re-implement challenge updates using order key (w/ CTFd patch)

[sudoBash418]

In theory, it should be possible to patch CTFd to:

1. add an "order" integer field to tags/hints/flags/files
2. use that field to sort the objects displayed to players

This would make the process of updating these objects much cleaner:
Instead of re-creating entire lists (or giving up on ordering, as I have for files), we would only need to reassign the order fields.

This would also make it simpler to display pending changes more accurately in cctk.

The real work would be in patching CTFd to support this, but hopefully that's straightfoward enough. knock on wood