PEL: Implement CreatePELWithFFDCFiles

This D-Bus method on the org.open_power.Logging.PEL interface is the
same as the already existing createWithFFDCFiles method on the
xyz.openbmc_project.Logging.Create interface, except it also returns the
IDs of the newly created OpenBMC event log and PEL.

Code was added to track the IDs of the most recently added event log and
PEL so they they can be returned by the function.

Change-Id: I3a1e0d93f97aa1953ff8b10293b47e28f79edfb1
diff --git a/extensions/openpower-pels/repository.hpp b/extensions/openpower-pels/repository.hpp
index 9bb71e4..e2f497b 100644
--- a/extensions/openpower-pels/repository.hpp
+++ b/extensions/openpower-pels/repository.hpp
@@ -415,6 +415,16 @@
         return _logPath;
     }
 
+    /**
+     * @brief Returns the ID of the most recently added PEL.
+     *
+     * @return uint32_t - The PEL ID
+     */
+    uint32_t lastPelID() const
+    {
+        return _lastPelID;
+    }
+
   private:
     using PELUpdateFunc = std::function<void(PEL&)>;
 
@@ -560,6 +570,11 @@
      * @brief Statistics on the sizes of the stored PELs.
      */
     SizeStats _sizes;
+
+    /**
+     * @brief The ID of the most recently added PEL.
+     */
+    uint32_t _lastPelID = 0;
 };
 
 } // namespace pels