That page is somewhat misleading. MDM is one way to install configuration profiles, but you can also install them by hand. No signing required, either. You can just stick that XML in a file with extension .mobileconfig, then double-click the file, and it will prompt you to install it.

Or download a signed version from here (not my site):

https://georgegarside.com/blog/macos/sierra-console-private/...