These changes add basic CDI integration to the docker daemon.
A cdi driver is added to handle cdi device requests. This
is gated by an experimental feature flag and is only supported on linux
This change also adds a CDISpecDirs (cdi-spec-dirs) option to the config.
This allows the default values of `/etc/cdi`, /var/run/cdi` to be overridden
which is useful for testing.
Signed-off-by: Evan Lezar <elezar@nvidia.com>