Feature request: verification through LinkedIn

I'm thinking that one way to make key base.io more visible might be to appeal to audiences outside the core reddit / hacker news / developer that current verification appeals to. LinkedIn might be a good place to get such broader appeal. While there's no easy place in a linkedin profile to add a signed block for verification, it may be possible to use the Advice for Contacting part of the profile, or even (gasp!) stegging the signed block into the profile image (though that would take some guidance for many users). So, though I'm not sure the best way _how_ to do it, the _what_ of the feature request sounds simple...

No implementation files, tests, or entry points are named. Start by clarifying which LinkedIn profile mechanism should support verification and how it would fit the existing Keybase verification flow; the issue is done only once the supported workflow and acceptance criteria are defined.

Written by the indexing model from the issue text.