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/common/flow_sort.go b/ponsim/v2/common/flow_sort.go
new file mode 100644
index 0000000..f62f7ca
--- /dev/null
+++ b/ponsim/v2/common/flow_sort.go
@@ -0,0 +1,17 @@
+package common
+
+import (
+	"github.com/opencord/voltha/protos/go/openflow_13"
+)
+
+type SortByPriority []*openflow_13.OfpFlowStats
+
+func (s SortByPriority) Len() int {
+	return len(s)
+}
+func (s SortByPriority) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+func (s SortByPriority) Less(i, j int) bool {
+	return s[i].Priority < s[j].Priority
+}