Imports of rootlesskit-docker-proxy command

PathSynopsis
contextPackage context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes.
flagPackage flag implements command-line flag parsing.
github.com/rootless-containers/rootlesskit/pkg/api/client
github.com/rootless-containers/rootlesskit/pkg/port
logPackage log implements a simple logging package.
osPackage os provides a platform-independent interface to operating system functionality.
os/execPackage exec runs external commands.
os/signalPackage signal implements access to incoming signals.
path/filepathPackage filepath implements utility routines for manipulating filename paths in a way compatible with the target operating system-defined file paths.
strconvPackage strconv implements conversions to and from string representations of basic data types.
syscallPackage syscall contains an interface to the low-level operating system primitives.