Add ability to bulk export (and import) Secrets via CSV

[hmhackmaster]

It would be a great feature to be able to export (and import) the most recent version of a set of secrets.

I am sure there benefits to exporting and importing Certificates and Keys as well, but those may introduce additional complexity (especially on the import). As Secrets contain just strings (Name, Identifier, Version, Secret), I figure that would be an easier first step.

Additionally, my specific need only requires exporting of Secrets, but I believe importing Secrets would be of broader use as well.

This ask was also made on Reddit by another user a while ago; linking it here just for posterity: https://www.reddit.com/r/AZURE/comments/1eotuvy/comment/lhgxa9w/

Thanks so much!