would like keybase CLI command to retrieve public key of another user

Yes, I can use keybase CLI to send e-mail, but maybe I want to use my Mail.app with GPG extension - and the user's keybase-uploaded key is not present in the usual key servers.

I did it manually through the API, finding the GPG block and converting the \n in the JSON to real newlines, and was able to import it, but would be nice to have a `keybase getkey ` command.

Start by locating the Keybase CLI command entry point and the API response containing the user's uploaded GPG block. Verify how the block is converted for import, then define completion as a `keybase getkey ` command that retrieves and outputs the public key.

Written by the indexing model from the issue text.