Support analyzing vue-class-component

Continuing #1083

ComponentInfo is not able to analyze vue-class-component yet.

The source looks like below, so it needs a different AST visitor. Maybe we can use typing from vue-class-component to analyze it.

@Component({
  props: {
    propMessage: String
  }
})
export default class App extends Vue {
  // initial data
  msg = 123

  // use prop values for initial data
  helloMsg = 'Hello, ' + this.propMessage

  // lifecycle hook
  mounted () {
    this.greet()
  }

  // computed
  get computedMsg () {
    return 'computed ' + this.msg
  }

  // method
  greet () {
    alert('greeting: ' + this.msg)
  }
}

[dennis2k]

It is also important to note that vue-class-component is often used along with the vue-property-decorator for defining props

[octref]

I’d like to limit this issue to only vue-class-component, which is officially supported.

There are many decorator libraries such as https://github.com/kaorun343/vue-property-decorator, https://github.com/itsFrank/vue-typescript, and one in the upcoming Vue 3 https://github.com/vuejs/rfcs/pull/17. Supporting them all is likely a lot of maintenance.