Convert the old mirror syncing queue to the more modern queue format.
Fix a bug in the from the repo-archive queue PR - the assumption was made that uniqueness could be enforced with by checking equality in a map in channel unique queues - however this only works for primitive types - which was the initial intention but is an imperfect. This is fixed by marshalling the data and placing the martialled data in the unique map instead.
The documentation is also updated to add information about the deprecated configuration values.
Signed-off-by: Andrew Thornton <art27@cantab.net>
7117c7774a