core: drop std::function and ndn::Exclude from common.hpp, add ndn::optional

Change-Id: Ie3983d8b6f9929430efd8ada8d942e3f95755cd4
diff --git a/daemon/mgmt/face-manager.cpp b/daemon/mgmt/face-manager.cpp
index 9d68256..76fac1c 100644
--- a/daemon/mgmt/face-manager.cpp
+++ b/daemon/mgmt/face-manager.cpp
@@ -88,7 +88,7 @@
     return;
   }
 
-  ndn::optional<FaceUri> localUri;
+  optional<FaceUri> localUri;
   if (parameters.hasLocalUri()) {
     localUri = FaceUri{};