Move function from network manager to utility function

Function which fetches the interface address from the system.
Add some types to types.hpp

Change-Id: Ie2c02980a9fd7a0aaeafa22d93bc758b5c79fd04
Signed-off-by: Ratan Gupta <ratagupt@in.ibm.com>
diff --git a/util.hpp b/util.hpp
index fb511fe..6f27af9 100644
--- a/util.hpp
+++ b/util.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <unistd.h>
+#include "types.hpp"
 
 namespace phosphor
 {
@@ -36,6 +37,11 @@
 std::string getNetworkID(int addressFamily, const std::string& ipaddress,
                          uint8_t prefix);
 
+/** @brief Get all the interfaces from the system.
+ *  @returns list of interface names.
+ */
+IntfAddrMap getInterfaceAddrs();
+
 } //namespace network
 
 class Descriptor