ItemUpdater: Implement Software.Extended Version

- Add Extended version in the MANIFEST
- Create an ExtendedVersion object
- Populate the ExtendedVersion object from MANIFEST

Resolves openbmc/openbmc#1401

Change-Id: Icb21e51a2a74c94f54ffecbd9057add4a0d3d694
Signed-off-by: Saqib Khan <khansa@us.ibm.com>
diff --git a/item_updater.hpp b/item_updater.hpp
index 091e31d..5afb96d 100755
--- a/item_updater.hpp
+++ b/item_updater.hpp
@@ -52,6 +52,16 @@
                                     void* userData,
                                     sd_bus_error* retError);
 
+        /**
+         * @brief Get the extended version from the specified file.
+         *
+         * @param[in] manifestFilePath  - File to read.
+         *
+         * @return The extended version.
+         */
+        static std::string getExtendedVersion(const std::string&
+                                               manifestFilePath);
+
         /** @brief Persistent sdbusplus DBus bus connection. */
         sdbusplus::bus::bus& busItem;