Better handle PII being turned off

[bmtcril]

Right now PII is off by default, however we have 2 dashboards that rely heavily on that data and look broken without it. We have 2 choices that I can see:

1- Turn those dashboards off when PII is off (but allow overrides)
2- Replace the PII with some kind of placeholders

Complications for 2:

• In order to make the cross filters work they would need to be unique somehow per user, but not in a way that exposes PII
• Any strings like "unknown" or "hidden" that we might need to use would need to be translatable, which can be a challenge

A possible way to do this is take some part of the user's per-course UUID and use that when the PII isn't present, but that does get hard to read and unless we hash it somehow will potentially expose enough of that key to be a privacy concern.

We should try to come up with a solution for this in the short term as it's a pretty painful issue.