Provide gem commands to automate generating and uploading developer keys

[postmodern]

Provide a gem command for setting up a developer key:

gpg --gen-key
gpg --keyserver pool.sks-keyservers.net --send-keys 0xDEADBEEF

[grant-olson]

I've been thinking about this some.

I would like some more gpg level commands built into the plug-in. But I'm not sure if I like the idea of auto-publishing someone's contact info to the keyservers, when they might not realize the implications. I also feel like you shouldn't publish to keyservers until you've made backup and revocation certs, so it's always going to be a manual process.

Maybe there could be a more interactive solution, or maybe a detailed help message when you run a sign command and clearly don't have a private key, or maybe a gpg-help command that spits out a bunch of useful information.

Will continue to background process though. Any input or suggestions are welcome.