Transit Key Export support

[cgraving]

I could seem to find a means to get this to work, but I am looking to read the actual transit key, possibly past versions, force a rotate and other transit operations. I mark a transit key as exportable, but when I try to read it keeps trying to put the "data" in the url as it if was a secret. Is there a way to read transit keys, latest or version? Rotate them? I would love to see this functionality if not.