Remove unused collections stuff

This was a beta api that didn't work out.

Test plan:
  canvas should still work (sorry, this touches lots of stuff)

Change-Id: I31680b83f72f6d739ce74735ba40d7a760debb33
Reviewed-on: https://gerrit.instructure.com/29506
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jon Jensen <jon@instructure.com>
QA-Review: Caleb Guanzon <cguanzon@instructure.com>
Product-Review: Cameron Matheson <cameron@instructure.com>