After moving to the flags package for command line argument parsing NFD
accepts command line arguments (flags) starting with a single dash (e.g.
-no-publish in addition to --no-publish). Even if double-dash can be
used the single-dash version is printed e.g. in the usage string (from
-h, -help) so align documentation with that.
This can be used to help running multiple parallel NFD deployments in
the same cluster. The flag changes the node annotation namespace to
<instance>.nfd.node.kubernetes.io allowing different nfd-master intances
to store metadata in separate annotations.
