Filter Solum resources by project ID

Prevent queries from returning resources that aren't
in the user's project/tenant, unless that user is an
administrator.

To this end, the Userlog model now bears a
project_id like most of our other resources, and
three regular users with their own tenants have been
created to demonstrate the mutual exclusion of their
resources.

Change-Id: I3f2c67deecd2750eea275a874ea6a020dea3a967
Merge "Filter Solum resources by project ID"