Of note: The rpm/yum thing seems to be coupled, so I put it into one
function that tries the yum helper and uses the rpm path otherwise.
Zypper is already its own thing, so this should only be used for yum
and probably dnf (does that still have the helper?)
Zypper can be dropped, as that already used a separate function in the file.
Apk can just be inlined - it's literally one line for installed and another for all packages.
This function doesn't make any sense.
Most things that expect package names expect package names for *one
specific package manager*.
It only happens to work, most of the time, because most people only
have one package manager installed.
