This task concerns only URL routing. Since the rest of components (state, UI, AQS requests...) are not ready for this change, the routing should be just able to parse a list of projects, as well as a single project, materialize it internally as an array, and redirect the state to the first wiki specified.

e.g:

https://stats.wikimedia.org/#/en.wikivoyage,es.wikipedia,eu.wikipedia/reading/total-page-views/normal|bar|2-year|~total|monthly

should change itself to:

https://stats.wikimedia.org/#/en.wikivoyage/reading/total-page-views/normal|bar|2-year|~total|monthly

For now there's no need to change anything in the UI to reflect this.