Add method for user's to 'report offers' with decentralized banlist offchain + hide/show reported items

[dwasyluk]

Provide a way for users to report wasted offers like the ones shown above. Reports would be sent to the Syscoin team. If an item is blacklisted by the team due to reports from users it will not show up in the browse view unless the 'hide blacklisted items' filter is turned off. The blacklist should be driven by an offchain data source. The banlist should be configurable. The banlist should follow a spec so anyone can create their own list.