Generate web-types.json for WebStorm, and files vetur-tags.json and vetur-attributes.json for Vetur

[lancegliser]

What problem does this feature solve?

IntellJ provides support for web components through it's web-types package:
https://github.com/JetBrains/web-types

More popular plugins seem to provide their own via scripts:
https://github.com/bootstrap-vue/bootstrap-vue/blob/dev/scripts/create-web-types.js
https://github.com/vuetifyjs/vuetify/blob/master/packages/api-generator/src/index.js

I'd like to see the Vue rollup functionality generate these required files so users can seamlessly export components that will include IDE support.

What does the proposed API look like?

Per the spec provided by JetBrains and Vueter, we have to generate files and have them referenced in package.json. We can use the transform hooks to collect the data, then use a final write hook to create the files as specified in the package.json if they are defined.