Define hex helper utils

This commit attempts to optimize some code and reduce our dependence on
boost libraries, as the coding standard recommends.  It does this by
introducing a new method, intToHexString, which is a greatly simplified
"to hex" converter that doesn't require std::locale, or stream buffers,
and is very efficient.  This deletes our need for boost::format, as well
as our need for boost::lexical_cast, both of which are fairly heavy
libraries.

Tested:
Unit tests pass.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I3b0f6eeb10256f87320adcc0ae9396f6bcbc8740
diff --git a/meson.build b/meson.build
index 9c69257..7673112 100644
--- a/meson.build
+++ b/meson.build
@@ -359,6 +359,7 @@
   'redfish-core/ut/lock_test.cpp',
   'redfish-core/ut/configfile_test.cpp',
   'redfish-core/ut/time_utils_test.cpp',
+  'redfish-core/ut/hex_utils_test.cpp',
   'http/ut/utility_test.cpp'
 ]