Initial exploration of BouncyCastle OpenPGP.

Just some basic load keyring/print key info functionality so far.
Checking in a bunch of crypto work.
Upgrade BouncyCastle library versions.
Fix some bugs in vault.crypto/print-key-info.
Signature generation, encoding, and decoding.
Implement PGP signature verification.
Add cryptography docs.
Update objects doc.
Rename schema doc to data-structures.
Clean up crypto ns a bit.
Merge branch 'crypto-work' into develop
Allow memory stores in configs.