Add sel entry

Add sel entry for ipmi raw command

Tested:`ipmitool raw 0x0a 0x44 0x00 0x01 0x02 0x00 0x00 0x00
0x00 0x20 0x00 0x04 0x14 0x8a 0x6f 0x00 0x00 0x00` for power_button
pressed,`ipmitool sel list` can see
 1 | 01/24/21 | 02:02:06 UTC | Button #0x8a | Power Button pressed | Asserted

Signed-off-by: Lotus Xu <xuxiaohan@bytedance.com>
Change-Id: I5a6bff109e5d12707a3a74570e6b7a584c7117bf
diff --git a/selutility.hpp b/selutility.hpp
index 06fc453..91c4eaf 100644
--- a/selutility.hpp
+++ b/selutility.hpp
@@ -2,8 +2,11 @@
 
 #include <chrono>
 #include <cstdint>
+#include <iomanip>
+#include <iostream>
 #include <ipmid/types.hpp>
 #include <sdbusplus/server.hpp>
+#include <sstream>
 
 namespace ipmi
 {
@@ -167,6 +170,17 @@
  */
 void readLoggingObjectPaths(ObjectPaths& paths);
 
+template <typename T>
+std::string toHexStr(const T& data)
+{
+    std::stringstream stream;
+    stream << std::hex << std::uppercase << std::setfill('0');
+    for (const auto& v : data)
+    {
+        stream << std::setw(2) << static_cast<int>(v);
+    }
+    return stream.str();
+}
 namespace internal
 {