Support IPNS

[MayeulC]

Hello, I would like to generate a vanity IPNS, kind of like scallion did for ToR. Would it be possible to adjust the code to check against the generated IPNS, instead of peer ID?

Edit: temporarily closed as I re-read the repo title and thought that was already supported.

Edit: I implemented something from the code that works quite well. I'll see about making a PR, but:

• I deleted a big chunk of the program (argument parsing, I write a regex inline instead)
• There is no license. Could you add one? I suggest MIT.