This commit consists of:
1) Dockerizing the netconf server
2) Update proto2yang to support module imports
3) Provide a set of yang modules derived from the proto files in voltha.
   These files as well as the slight mmodifications to the proto files are
   provided in the experiments/netconf/proto2yang directory
4) Code to automatically pull proto files from voltha into the netconf server,
   compiles them and produce the yang equivalent files.
5) Add a getvoltha netconf API to provide voltha state information (basic at
   this time).  There is potential to make this generic once we experiment
   with additional APIs

Change-Id: I94f3a1f871b8025ad675d5f9b9b626d1be8b8d36
diff --git a/experiments/netconf/proto2yang/health.proto b/experiments/netconf/proto2yang/health.proto
new file mode 100644
index 0000000..19383a9
--- /dev/null
+++ b/experiments/netconf/proto2yang/health.proto
@@ -0,0 +1,34 @@
+syntax = "proto3";
+
+package voltha;
+
+import "google/api/annotations.proto";
+import "google/protobuf/empty.proto";
+import "meta.proto";
+
+// Encode health status of a Voltha instance
+message HealthStatus {
+
+    // Health states
+    enum HealthState {
+        HEALTHY = 0;  // The instance is healthy
+        OVERLOADED = 1;  // The instance is overloaded, decrease query rate
+        DYING = 2;  // The instance is in a critical condition, do not use it
+    }
+
+    // Current state of health of this Voltha instance
+    HealthState state = 1 [(access) = READ_ONLY];
+}
+
+// Health related services
+service HealthService {
+
+    // Return current health status of a Voltha instance
+    rpc GetHealthStatus(google.protobuf.Empty) returns (HealthStatus) {
+        option (google.api.http) = {
+            get: "/health"
+        };
+    }
+
+}
+