Implement bundle system (how to publish the package)

[kiaking]

So, how should we publish the package? Here is the spec idea.

Vue Theme will expose many components that can be used by external packages. And they can import them like this.

import { VTButton } from 'vue-theme'

Q1. Is this what we really want? Is there any other way to consume Vue Theme components?
Q2. If yes, how can we bundle the package? Rollup I guess, but I'm not familiar with publishing Vue components, so if there's any advice, that would be awesome 🙌

[yyx990803]

For now we can simply distribute it unbundled.