For future work, we need multiple implementations of the OCI
runtime, not just a Conmon-wrapped runtime matching the runc CLI.
As part of this, do some refactoring on the interface for exec
(move to a struct, not a massive list of arguments). Also, add
'all' support to Kill and Stop (supported by runc and used a bit
internally for removing containers).
Signed-off-by: Matthew Heon <matthew.heon@pm.me>
