Add JS tool to download users and articles for a single user's courses from Wiki Education Dashboard

[ragesoss]

For example, I want to download all the users (students and instructors, excluding Wiki Education staff) and edited articles from the courses of User:Glenn.dolphin: https://dashboard.wikiedu.org/users/Glenn.dolphin

The input should take a username (with or without User: prefix) or a Dashboard user profile URL like the one above.

It should have a select to choose between dashboard.wikiedu.org and outreachdashboard.wmflabs.org, defaulting to dashboard.wikiedu.org (and entering a URL should automatically update that select to the right one).