Move os_base into turnip

This branch copied the latest 2.x branch of os_base into turnip and adds code so that make-install-profile will set it as profile_base.  In other words, when you run `bin/make-install-profile foobar foobar "FooBar" "Foo description bar"` you will now have a base feature of `foobar/modules/features/foobar_base`