[Merge] ~juliank/software-properties:refresh-keys into software-properties:ubuntu/master

[Julian Andres Klode]

Cloud Archive support would be nice too
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https://code.launchpad.net/~juliank/software-properties/+git/software-properties/+merge/471412
Your team Ubuntu Core Development Team is requested to review the proposed merge of ~juliank/software-properties:refresh-keys into software-properties:ubuntu/master.