[RFR] Interacting with DirP

This is a working prototype.  This PR enables the PGP app to upload to and query a directory provider.  Currently this uses https://github.com/spectralsun/valorem-vis as the key server aka directory provider.  

This is the list of known issues and caveats of the prototype:

* https://github.com/privly/privly-applications/issues/42  Signing and verifying messages
* https://github.com/privly/privly-applications/issues/62  Key Expiration
* https://github.com/privly/privly-applications/issues/63  Signing in with persona
* https://github.com/privly/privly-applications/issues/64  Assess if persona private key is captured
* https://github.com/privly/privly-applications/issues/65  Entropy source
* https://github.com/privly/privly-applications/issues/66  UI corrections
* https://github.com/privly/privly-applications/issues/67  namespace storage
* https://github.com/privly/privly-applications/issues/68  Autocomplete form
* https://github.com/privly/privly-applications/issues/69  Change http request method