Refactor shim v2 to load and register plugins.
Update init shim interface to not require task service implementation on
returned service, but register as plugin if it is.
Signed-off-by: Derek McGowan <derek@mcg.dev>
This change is needed for running the latest containerd inside Docker
that is not aware of the recently added caps (BPF, PERFMON, CHECKPOINT_RESTORE).
Without this change, containerd inside Docker fails to run containers with
"apply caps: operation not permitted" error.
See kubernetes-sigs/kind 2058
NOTE: The caller process of this function is now assumed to be as
privileged as possible.
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
