scripts: convert helper scripts to python3

This patch ports helper scripts from python2 to python3
with following changes:

- print should be used with () in python3
- resolved bytes-like object is required, not 'str'
- added python3 header

ZEP-2054

Signed-off-by: punit vara <punit.vara@intel.com>
diff --git a/scripts/diffconfig b/scripts/diffconfig
index a57a4c7..94c3f83 100755
--- a/scripts/diffconfig
+++ b/scripts/diffconfig
@@ -1,4 +1,4 @@
-#!/usr/bin/env python2
+#!/usr/bin/env python3
 #
 # diffconfig - a tool to compare .config files.
 #