Start work on Container and Process model

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

execution/executors/executors.go

@@ -0,0 +1,13 @@
+package executors
+
+import "github.com/docker/containerd"
+
+var executors = make(map[string]func() containerd.Executor)
+
+func Register(name string, e func() containerd.Executor) {
+	executors[name] = e
+}
+
+func Get(name string) func() containerd.Executor {
+	return executors[name]
+}