Extract version deployment into a new addon

[josemarluedke]

The deploy pipeline with the version support is pretty awesome. The community would benefit if we extracted that functionality into a new addon that could be used outside of addon-docs. It probably could be an ember-cli-deploy plugin.

The Docfy project (in the Ember integration) would probably use something like that to support versioned docs.

[RobbieTheWagner]

@josemarluedke sounds like a great idea to me! I'm not well versed in how that bit works though, and haven't done much with ember-cli-deploy. Is this something you would like to take on?