net: Providing an interface for mapLocalHost

Contributes to #564 by providing an interface for mapLocalHost
through net -> node interface -> clientModel. Later this value can be
read by GUI to show the local addresses.

src/node/interfaces.cpp

@@ -281,6 +281,13 @@ public:
         }
         return false;
     }
+    std::map<CNetAddr, LocalServiceInfo> getNetLocalAddresses() override
+    {
+        if (m_context->connman)
+            return m_context->connman->getNetLocalAddresses();
+        else
+            return {};
+    }
     int getNumBlocks() override
     {
         LOCK(::cs_main);