Cloud identity docs

This PR adds the Cloud Identity service to our documentation. We need the following language samples:

- [x] Bash
- [ ] C#
- [x] Golang
- [ ] Java
- [ ] Javascript
- [x] PHP
- [ ] Python
- [x] Ruby
This is a pretty bad reason to use **List Users**. A better example would be to output the user name and ID for the available users (e.g. one per line).