Lookup implementation

PR @zancas's work on lookup. PRs make it easy to do code reviews when new commits are pushed.
@dionyziz see messages in slack. authentication doesn't depend on HTTPS (which can't provide it). it's done based on a signature that's included either in the JSON returned, or an HTTP header.

- Yes, HTTPS can still be done to additionally encrypt the data
- As mentioned in Slack (plz read those messages from me in #dev), this is something that's TBD, and can be done real soon if you need it ASAP.