Add the EnvUser with tests. Create an Environment user during bootstrap

Added the EnvUser doc

Support for setting the last login time for the EnvUser

Added a factory for adding the envuser

Admin EnvUser gets added at bootstrap time

Removed a couple of attributes from the upgrade package that no longer needed to be there

Actually, no. We do want a *time.Time.  It makes sense for one that is optional. Using IsZero is a royal PITA, and didn't work consistently as mongo was changing the timezone on selection.  I found out the hard way, and using a pointer was much cleaner and more effective.  It is also what we are using on the User doc.