This PR fixes the CNI plugin fingerprinter to take into account the fact
that the cni_path config can be a multi-path (e.g. `/foo:/bar:/baz`).
Accumulate plugins from each of the possible path elements. If scanning
any of the named directory fails, the fingerprinter fails.
Fixes#16083
No CL/BP - has not shipped yet.
This PR adds a fingerprinter to set the attribute
"plugins.cni.version.<name>" => "<version>"
for each CNI plugin in <client>.cni_path (/opt/cni/bin by default).
Etienne Bruines