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

Yep, I've seen later that it's in testing, so it's ok. Another way would be to always pass the params. So one can do

```
MakeEnvUser(EnvUserParams{})
```

as well as

```
MakeEnvUser(EnvUserParams{User: "foo"})
```