this provides a simple way to handle incoming
os signas using context

Signed-off-by: adrianc <adrianc@nvidia.com>

- if cleanup-config-on-exit is set delete generated multus
  config file on exit.

- add an option to skip watch for master cni config and kubeconfig
  as cleanup-config-on-exit with multus-conf-file=auto also triggered
  the watch for cases when deletion of multus config is desired but watch isnt

- setup signal handling to allow config file cleanup on exit

Signed-off-by: adrianc <adrianc@nvidia.com>

Signed-off-by: adrianc <adrianc@nvidia.com>