Explicit facilities for offline judging

[julianmichael]

Still need to think about exactly what this will look like (and might break into separate issues), but:

• We need a way for debates to end with no online judge (perhaps set a fixed length in the rules)?
• Allow debaters to end the debate by mutual agreement?
• We need a separate debate panel for offline judging only (all completed debates can be offline-judged)
• We need to add server state to hold offline judging results (multiple judges possible per debate)
• We need to have the offline judging UI time the judges (and maybe track how they drag the probabilities over time? If we want live data?)
• We could add an alternative offline judging setting, where the offline judges simulate online judging, stepping through the debate and paying a cost at each turn. This would probably be mutex with the timed setup.

[julianmichael]

Made a bunch of progress on this. Main remaining things are:

• Augment debate panel with the ability to do offline judging (timed judging in particular)
• Figure out a way to expose this functionality in the lobby

[julianmichael]

Ok, the lobby is mostly done. What remains:

• Track who has read what story and who is assigned to debate them, so we can filter out the debates they're not eligible to judge offline.
• Implement the judging variant of the debate panel interface.

[julianmichael]

Tracking is done. Now just need to implement:

• Assignment of offline judges to debates (in creation panel, and as a distinguishing factor / RoomHeading in the lobby)
• Actual judging interface

[julianmichael]

A load of progress now. Judging interface done, lobby stuff mostly done. Remaining to-dos:

• assignment of offline judges in debate creation panel
• reassignment in admin/facilitator mode

Then, need to check on functionality:

• You shouldn't be able to start the debate as an offline judge if it's incomplete
• You shouldn't be able to join the debate room at all (by clicking) as an offline judge if it's incomplete

Almost there!