Integration with OpenKeyChain for sharing journals

[tasn]

I would love having OpenKeyChain support for sharing journals, so when you share a journal, you could search your verified PGP contacts other than the EteSync user info for public keys. An additional bonus point would be to be able to publish your PGP key as the public key to use, instead of generating a new one for EteSync like we do now.

I don't have time to tackle this one myself, as I have other, more important ideas and features in the pipeline. However, I think this issue could be interesting enough for contributors to collaborate on.