VOL-291 : PON simulator refactoring for cluster integration

- Added ponsim build target in Makefile
- Added new option to vcore to select comm type with ponsim
- Modified all proto files to include destination go package

Amendments:

- Clean up based on review comments
- Properly close GRPC connections in ponsim_olt adapter
- Added voltha namespace to some k8s templates

Change-Id: I2f349fa7b3550a8a8cc8fc676cc896f33fbb9372
diff --git a/ponsim/v2/core/ponsim_device_type.go b/ponsim/v2/core/ponsim_device_type.go
new file mode 100644
index 0000000..306440c
--- /dev/null
+++ b/ponsim/v2/core/ponsim_device_type.go
@@ -0,0 +1,17 @@
+package core
+
+type PonSimDeviceType uint8
+
+const (
+	OLT PonSimDeviceType = iota
+	ONU
+)
+
+var enum_ponsim_device_types = []string{
+	"OLT",
+	"ONU",
+}
+
+func (t PonSimDeviceType) String() string {
+	return enum_ponsim_device_types[t]
+}