Refactoring file structure for protobufs.

Change-Id: I50daf100d54750f97158304d87813e67861b1422
diff --git a/incubator/protobuf/models/src/main/proto/PortDescriptionProto.proto b/incubator/protobuf/models/src/main/proto/PortDescriptionProto.proto
new file mode 100644
index 0000000..065ef67
--- /dev/null
+++ b/incubator/protobuf/models/src/main/proto/PortDescriptionProto.proto
@@ -0,0 +1,15 @@
+syntax = "proto3";
+option java_package = "org.onosproject.grpc.net.models";
+
+package Port;
+
+import "PortEnums.proto";
+
+message PortDescription {
+    // PortNumber as String PortNumber#toString
+    string port_number = 1;
+    bool is_enabled = 2;
+    Port.PortType type = 3;
+    int64 port_speed = 4;
+    map<string, string> annotations = 8;
+}
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