container: Store and fetch container's process
container: Store and fetch container's process

This patch provides some getter/setter to modify container's process
value from outside of the virtcontainers library. It is designed to
be called by a runtime implementation so that it can store and fetch
process ID and token.

Signed-off-by: Sebastien Boeuf <90b401417360b1924ef3f520ddee932686110f85@intel.com>

containers/virtcontainers,wcwxyz/virtcontainers,wcwxyz/virtcontainers,containers/virtcontainers,wcwxyz/virtcontainers