There will be a way to retrieve the list of all system installations,
not just the default one, so we rename this for backward compatibility.
Note that some (most?) of the places where we will be now using this
renamed function will likely have to migrate to using specific system
installations, but we don't have the necessary APIs yet so we do this
as an initial step to all the incremental changes that will come next.
The info file is always standalone, as it never needs to stack on top
of another context. This means we can remove all "negative" attributes
such as "shared=!network", making it easier to parse this file.