Update User api to respect default settings

-API now respects default_projects_limit, default_can_create_group, and default_can_create_team

Change-Id: I059d060d576df1050e5371e707381c5e8c608a7a
Update to only provide one way to get a default user

-calling build_user will now apply defaults and only override them if as: :admin is set

Change-Id: Id1d938c0967752ecc14370af54f2d88128d18c44