[DAEMON-89] Migrate to Lerna.js

I've been resisting the urge to jump to Lerna.js fearing it won't handle some of the edge cases, but once the daemon is released, managing and coordinating all the package releases is going to become more complicated. Need to understand Lerna's support for Yarn since we depend on yarn check. npm 5 does not yet support node_module integrity checks. Need to figure how to use Lerna.js and configure package dependencies. We will also probably ditch gulp (which isn't a bad thing) in favor of NPM scripts and a scripts directory. Everything in appcd-gulp will be moved to the scripts directory. The hope is this will give us a more manageable repo, faster builds, coordinated publishing, and removes the dependency on a globally installed gulp.