Add module display name to module related server events

This information will likely be used frequently for analytics purposes, so we would like to denormalize here to avoid having to join with the modulestore later.

We would like this feature to make it in to the release tomorrow.

A few notes:

* Wasn't sure where the best place to put this logic is.  Very open to suggestions.
* I figured the best way to communicate what we are trying to do was to submit a diff.  I'm not attached to any of this.
* Once the approach is approved, I'll nail it down with some tests etc.

Fixes: AN-594
Reviewers: @cpennington, @rocha, @brianhw