Detect OS family without lsb_release

[MicahElliott]

Package lsb_release is the only dep that's not installed on minimal containers, and anyone who tries Pacrcat in docker will have to know to add it. So instead of relying on it, could do something like: https://stackoverflow.com/a/26988390/326516

Thanks @dysmento for the idea! Mentioned chezmoi's technique which is really neat, but it has go to do its handywork.