mgmt: handle rib/announce command

This commit adds logic to NFD so it can handle the new Prefix
Announcement protocol, which are commands sent to rib/announce
with Prefix Announcement object in the Application Parameters.

Refs: #4650
Change-Id: I2a306eb2c3eeb638cc789329d998bfa278880ca6
diff --git a/daemon/mgmt/rib-manager.hpp b/daemon/mgmt/rib-manager.hpp
index a7edc22..3b348a1 100644
--- a/daemon/mgmt/rib-manager.hpp
+++ b/daemon/mgmt/rib-manager.hpp
@@ -212,6 +212,13 @@
                   const CommandContinuation& done);
 
   /**
+   * \brief Serve `rib/announce` command.
+   */
+  void
+  announceEntry(const Interest& interest, const ndn::nfd::RibAnnounceParameters& parameters,
+                const CommandContinuation& done);
+
+  /**
    * \brief Serve `rib/list` dataset.
    */
   void