Move event types constants into single file

Move all constants for event types to types.go for easier code
readability and maintainance.

Signed-off-by: Zhang Wei <zhangwei555@huawei.com>

supervisor/types.go

@@ -0,0 +1,12 @@
+package supervisor
+
+// State constants used in Event types
+const (
+	StateStart        = "start-container"
+	StatePause        = "pause"
+	StateResume       = "resume"
+	StateExit         = "exit"
+	StateStartProcess = "start-process"
+	StateOOM          = "oom"
+	StateLive         = "live"
+)