Add support for `to.software_function`

[ofalvai]

Karabiner now supports a native way to sleep the system (instead of the AppleScript workaround): https://karabiner-elements.pqrs.org/docs/json/complex-modifications-manipulator-definition/to/software_function/iokit_power_management_sleep_system/

It would be great to use this syntax in Goku with other software_functions.