This command is for TPM secure booting, and does three things:
1) Figures out what sets of PCRs a node is supposed to include in
   its quote to get to the given state
2) Gives the node its (encrypted) identity key for use in generating
   the quote
3) Generates a noce for replay prevention, stores it in the database,
   and passes it back to the client

This version compiles, but it totally untested, so I'm sure it doesn't
work yet. I haven't added the database modifications to the schema file
yet, since it's not certain that I've got 'em right.