Refactoring file structure for protobufs.

Change-Id: I50daf100d54750f97158304d87813e67861b1422
diff --git a/incubator/protobuf/models/src/main/proto/PortProto.proto b/incubator/protobuf/models/src/main/proto/PortProto.proto
new file mode 100644
index 0000000..309e50b
--- /dev/null
+++ b/incubator/protobuf/models/src/main/proto/PortProto.proto
@@ -0,0 +1,16 @@
+syntax = "proto3";
+option java_package = "org.onosproject.grpc.net.models";
+
+package Port;
+
+import "PortEnums.proto";
+
+// Corresponds to org.onosproject.net.Port.
+message PortProto {
+    string port_number = 1;
+    bool is_enabled = 2;
+    Port.PortType type = 3;
+    int64 port_speed = 4;
+    map<string, string> annotations = 5;
+}
+