Use solid as export option

## Meta info

- Is this a bug or suggestion?: Suggestion
- Version (click on help icon in footer): 3.6.2
- Context - Web app, Chrome extension or both?: Web app

I recently heard about the [solid project](https://solid.mit.edu/), which from my point of view would fit together with this application. The idea of solid is to decouple the application and data storage, which is done by providing a common storage place ("Pods") to which the application is granted read/write access.

For the webmaker app this could be used to provide an online decentralized storage option. The implementation should be rather easy, because the server part is handled by the pods, and there is a [simple API](https://github.com/jeff-zucker/solid-file-client/) for reading/writing data to the pods. I myself haven't got much experience with solid though.