Remove use of unicode_literals as it is an anti-pattern

from __future__ unicode_literals leads to developer confusion as
developers no longer can tell whether a bare literal string is a byte
string or a unicode string.  Explicit marking as u"" or b"" is the way
to solve the same problem in the Ansbile codebase.

test/sanity/code-smell/no-unicode-literals.sh

@@ -0,0 +1,16 @@
+#!/bin/sh
+
+UNICODE_LITERALS_USERS=$(grep -r unicode_literals . \
+    --exclude-dir .git \
+    --exclude-dir .tox \
+    --exclude no-unicode-literals.sh \
+    --exclude no-unicode-literals.rst |
+    grep -v ./test/results \
+    )
+
+if [ "${UNICODE_LITERALS_USERS}" ]; then
+    echo "${UNICODE_LITERALS_USERS}"
+    exit 1
+fi
+
+exit 0