JSON parser for VPD manager app

This commit implements a parser which parse and store vpd JSON at the
launch of the application.
An applicatin specific parser is required to support write keyword
functionality as reverse mapping of JSON items is required.
In this case the user passes an invetory path and EEPROM VPD for that
inventory path needs to be extracted.

Signed-off-by: Sunny Srivastava <sunnsr25@in.ibm.com>
Change-Id: I7f91b45982c59dfb0d36fe8e80ebd7373a93f147
diff --git a/types.hpp b/types.hpp
index cfe0530..09217af 100644
--- a/types.hpp
+++ b/types.hpp
@@ -4,6 +4,7 @@
 #include <map>
 #include <sdbusplus/server.hpp>
 #include <string>
+#include <unordered_map>
 #include <vector>
 
 namespace openpower
@@ -31,6 +32,9 @@
 using Object = sdbusplus::message::object_path;
 using ObjectMap = std::map<Object, InterfaceMap>;
 
+using VPDfilepath = std::string;
+using FrusMap = std::unordered_map<Path, VPDfilepath>;
+
 using namespace std::string_literals;
 constexpr auto pimPath = "/xyz/openbmc_project/inventory";
 constexpr auto pimIntf = "xyz.openbmc_project.Inventory.Manager";