Change the rpc to accommodate for multiple wallets

[leonardotc]

Questions:

• How should the wallet (frontend) connect to peer? I imagine it would be the same way with other networks (aka the current wallet plugin is used, signs and interacts) which is different from hypermall that uses trac-peer own wallet. Is the "permissions" for this set in the contract iself?
• Current implementation follows the same principles of the previous one. One contract per instance. Is that ok for now?