Refactor to a Scuttlebot plugin

2x more deletions than additions!

To test this, add this `phoenix.js` script to the scuttlebot directory and give it execute perms: 

```js
#! /usr/bin/env node

var server = require('./index')(require('./config'))
server
  .use(require('./plugins/gossip'))
  .use(require('./plugins/replicate'))
  .use(require('./plugins/local'))
  .use(require('../phoenix'))
```

Phoenix isn't published as a module yet, so you'll just need point the last `require()` call to its directory.