tourney import only (WIP)

REST API done for this part, still need to write UI
@garsh0p @jhertz 

no auth integration yet; need to rebase onto master.

(other changes are still on the other branch, which I'll rebase onto this one at some point)
the frontend is usually gonna want the JSONs directly, without modifications, so there's no point in converting back and forth (the actual list of `PendingTournament` objects is the next method)