Fee voting settings from the configuration file

@tdfischer, @sublimator 
I know what you mean. There wouldn't be enough symbols in a namespace to justify the extra namespace. And there are no other nouns in the system that could be misconstrued for `Section`. I agree, if we add a lot more identifiers to the core rippled vocabulary we might want to rethink the choice of `Section`. But for now it seems appropriate and has the benefit of brevity.