Move runtime implementation types to pkg

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

container.go

@@ -1,48 +0,0 @@
-package containerd
-
-import (
-	"os"
-
-	"github.com/opencontainers/specs"
-)
-
-type Process interface {
-	Pid() (int, error)
-	Spec() specs.Process
-	Signal(os.Signal) error
-}
-type Status string
-
-const (
-	Paused  Status = "paused"
-	Running Status = "running"
-)
-
-type State struct {
-	Status Status `json:"status,omitempty"`
-}
-
-type Container interface {
-	// ID returns the container ID
-	ID() string
-	// Start starts the init process of the container
-	Start() error
-	// Path returns the path to the bundle
-	Path() string
-	// Pid returns the container's init process id
-	Pid() (int, error)
-	// SetExited sets the exit status of the container after it's init dies
-	SetExited(status int)
-	// Delete deletes the container
-	Delete() error
-	// Processes returns all the containers processes that have been added
-	Processes() ([]Process, error)
-	// RemoveProcess removes a specific process for the container because it exited
-	RemoveProcess(pid int) error
-	// State returns the containers runtime state
-	State() State
-	// Resume resumes a paused container
-	Resume() error
-	// Pause pauses a running container
-	Pause() error
-}