migrate to local service

[DevonJames]

1. just like its written now, when the user clicks a paywall button, the artifact's payment address is looked up (browser-react)
2. similar to how its written now, generate a new payment address (use bitcoin.js in browser-react instead of blocktrail hosted wallet)
3. just like its written now, when the new payment address receives a payment, trigger play/buy action (paywall-web, i think?)
4. totally different from how its written now, when the user ends their session (closes window, quits browser), do a sendmany transaction from the bitcoin.js wallet to the actual payment addresses