game/world/character: Implement the update IPersistable callback
game/world/character: Implement the update IPersistable callback

While the implementation is a bit inefficient, this patch does provide a
mechanism to update a character in the DAL. It does this by purging the
backend storage of any aggregate data items, then re-creating them. Since
some of these items are unlikely to change (such as attributes), this is
a bit overkill, but it should be sufficient for now.

matt-jordan/mjmud