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_interface.go b/ponsim/v2/core/ponsim_interface.go
new file mode 100644
index 0000000..d73d2ca
--- /dev/null
+++ b/ponsim/v2/core/ponsim_interface.go
@@ -0,0 +1,18 @@
+package core
+
+import (
+	"context"
+	"github.com/google/gopacket"
+)
+
+type PonSimInterface interface {
+	Start(context.Context)
+
+	Stop(context.Context)
+
+	GetAddress() string
+
+	GetPort() int32
+
+	Forward(context.Context, int, gopacket.Packet) error
+}