Migrate to a common timer class

This change pulls in sdeventplus and uses the timer implementation as
a drop in for the currently included timer.

Tested:
    Unit tests still build but are not currently running. Manually
    tested this change on a zaius machine and made sure timers went off.

Change-Id: I2808196581fc766843931403b83fead16926b0ae
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/types.hpp b/types.hpp
index b8038b4..9ffe5ad 100644
--- a/types.hpp
+++ b/types.hpp
@@ -8,6 +8,8 @@
 #include <list>
 #include <map>
 #include <memory>
+#include <sdeventplus/clock.hpp>
+#include <sdeventplus/utility/timer.hpp>
 #include <set>
 #include <string>
 #include <vector>
@@ -76,5 +78,7 @@
 using IntfAddrMap = std::map<IntfName, AddrList>;
 using InterfaceList = std::set<IntfName>;
 
+using Timer = sdeventplus::utility::Timer<sdeventplus::ClockId::Monotonic>;
+
 } // namespace network
 } // namespace phosphor