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

Would like a description here how it differs from the other User in state. Think of the new reader of the GoDoc or the maintainer of the code in two years.