Implement reasonable handling for bridge blocking

Currently the Lox distributor does not handle blocked bridges at all. This is due to two main issues. The first is that we do not yet have a well-established method for determining that a bridge is indeed blocked. The second is that when bridges are blocked, they are blocked in some locations and not others and we have not yet come to consensus on how this should be handled by Lox. For our alpha deployment however, we should have some kind of alpha solution. For now, we will assume some target country and search for whether or not that country appears in the blocked_in list that Lox will receive for each resource from rdsys. If the target country is in the list, the bridge will be marked as blocked.