Change lox-library functionality to replenish open-invitation bucket pool from hot-spare pool
Hot spares could replenish open-invitation buckets but currently are only reallocated to be migrated to after a blocking event. Perhaps the current functionality is the desired functionality, but if we're more likely to have open-invitation bridges blocked than user migrate to trusted buckets when their bridges become blocked, this might be something to consider. At the very least it could satisfy a condition in the case that there are no remaining open-invitation buckets. We should probably also flag that scenario so we can do something to get more bridges into the pool (hopefully).