Refactoring on `utils.cc' and adjacents

Completely removed the `utils.cc' by moving residual functions into
sub-classes of `utils/'

test/unit/unit.cc

@@ -28,9 +28,9 @@
 #include "common/modsecurity_test_results.h"
 #include "common/colors.h"
 #include "unit/unit_test.h"
-#include "src/utils.h"
 #include "utils/msc_string.h"
 
+
 using modsecurity::utils::String;
 using modsecurity_test::UnitTest;
 using modsecurity_test::ModSecurityTest;