Fix intro package

[wouterbles]

• Delete old stuff with linked application forms
• Check functionality of pending user intro package form

[marijnvanderhorst]

It looks like commit 4e5cab0 was pushed/merged into master in error at some point (probably by me haha). I'd suggest cherry-picking that commit to a new feature branch and reverting the commit on master. The feature was never fully finished, so work should continue on a feature branch instead. I'll hopefully find some time to do this at some point.

[wouterbles]

I think there are two partially finished implementations right?

1. Intro package stuff with linked application forms (this doesn't appear to be working)
2. "Hard-coded" intro package stuff stored with user (see pending user page). This appears to be working and I can download some info from the pending users page

So, we should probably settle on one implementation and delete the other. The application form one would be a bit more flexible, but might be more difficult to implement? What do you think?